Method and apparatus for receiving PPDU in which data is duplicated and to which phase rotation is applied in wireless LAN system

ABSTRACT

Proposed are a method and an apparatus for receiving a PPDU in a wireless LAN system. Specifically, a reception STA receives a PPDU from a transmission STA through a first band, and decodes the PPDU. The PPDU includes a preamble and a data field. The first band includes first to fourth sub-blocks. The data field includes first data for first and second sub-blocks and second data for third and fourth sub-blocks. The second data is generated on the basis of data obtaining by duplicating the first data and applying phase rotation to the third sub-block.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.18/010,982, filed on Dec. 16, 2022, which is a National Stageapplication under 35 U.S.C. § 371 of International Application No.PCT/KR2021/008247, filed on Jun. 30, 2021, which claims the benefit ofKorean Patent Application No. 10-2020-0081761, filed on Jul. 2, 2020,Korean Patent Application No. 10-2020-0086940, filed on Jul. 14, 2020,Korean Patent Application No. 10-2020-0087636, filed on Jul. 15, 2020,and Korean Patent Application No. 10-2020-0100001, filed on Aug. 10,2020. The disclosures of the prior applications are incorporated byreference in their entirety.

TECHNICAL FIELD

The present specification relates to a method for receiving a PPDU in awireless local area network (WLAN) system and, most particularly, to amethod and apparatus for receiving a PPDU in which data is duplicatedand phase rotation is applied.

BACKGROUND

A wireless local area network (WLAN) has been improved in various ways.For example, the IEEE 802.11ax standard proposed an improvedcommunication environment using orthogonal frequency division multipleaccess (OFDMA) and downlink multi-user multiple input multiple output(DL MU MIMO) techniques.

The present specification proposes a technical feature that can beutilized in a new communication standard. For example, the newcommunication standard may be an extreme high throughput (EHT) standardwhich is currently being discussed. The EHT standard may use anincreased bandwidth, an enhanced PHY layer protocol data unit (PPDU)structure, an enhanced sequence, a hybrid automatic repeat request(HARQ) scheme, or the like, which is newly proposed. The EHT standardmay be called the IEEE 802.11be standard.

In a new WLAN standard, an increased number of spatial streams may beused. In this case, in order to properly use the increased number ofspatial streams, a signaling technique in the WLAN system may need to beimproved.

SUMMARY

The present specification proposes a method and apparatus for receivinga PPDU in which data is duplicated and phase rotation is applied in awireless LAN system.

An example of the present specification proposes a method for receivinga PPDU in which data is duplicated and phase rotation is applied.

The present embodiment may be performed in a network environment inwhich a next generation WLAN system (IEEE 802.11be or EHT WLAN system)is supported. The next generation wireless LAN system is a WLAN systemthat is enhanced from an 802.11ax system and may, therefore, satisfybackward compatibility with the 802.11ax system.

This embodiment proposes a method and apparatus for duplicating andtransmitting data in order to increase a transmission distance intransmission of an EHT PPDU. The 802.11be wireless LAN system cansupport transmission in an indoor environment using low power in abroadband of 6 GHz. Accordingly, in order to obtain more reliableperformance, a method of repeatedly transmitting data in the frequencydomain in the EHT PPDU is proposed.

A receiving station (STA) receives a Physical Protocol Data Unit (PPDU)from a transmitting STA through a first band.

The receiving STA decodes the PPDU.

The PPDU may be an Extremely High Throughput (EHT) PPDU supporting an802.11be wireless LAN system. The PPDU includes a preamble and a datafield. The preamble is a Legacy-Short Training Field (L-STF), aLegacy-Long Training Field (L-LTF), a Legacy-Signal (L-SIG), anUniversal-Signal (U-SIG), an EHT-SIG, an EHT-STF and an EHT-LTF.

The first band includes first to fourth subblocks. The first to fourthsubblocks may be arranged in order of frequency from low to high. Thedata field includes first data for the first and second subblocks andsecond data for the third and fourth subblocks. The second data isgenerated based on data obtained by duplicating the first data andapplying phase rotation to the third subblock. A value of the phaserotation applied to the third subblock is −1. Phase rotation is notapplied to the remaining subblocks, i.e., the first, second, and fourthsubblocks (or simply multiplied by 1).

According to the embodiment proposed in this specification, bytransmitting a PPDU by applying phase rotation to data for a subblockhaving the third lowest frequency in the entire band, reliableperformance can be obtained even for transmission over a longerdistance. As a result, there is an effect of increasing the transmissionrange of the PPDU of the transmitter and improving overall performance.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an example of a transmitting apparatus and/or receivingapparatus of the present specification.

FIG. 2 is a conceptual view illustrating the structure of a wirelesslocal area network (WLAN).

FIG. 3 illustrates a general link setup process.

FIG. 4 illustrates an example of a PPDU used in an IEEE standard.

FIG. 5 illustrates a layout of resource units (RUs) used in a band of 20MHz.

FIG. 6 illustrates a layout of RUs used in a band of 40 MHz.

FIG. 7 illustrates a layout of RUs used in a band of 80 MHz.

FIG. 8 illustrates a structure of an HE-SIG-B field.

FIG. 9 illustrates an example in which a plurality of user STAs areallocated to the same RU through a MU-MIMO scheme.

FIG. 10 illustrates an example of a PPDU used in the presentspecification.

FIG. 11 illustrates an example of a modified transmission device and/orreceiving device of the present specification.

FIG. 12 shows an example of a PHY transmission procedure for a HE SUPPDU.

FIG. 13 shows an example of a block diagram of a transmitter generatinga data field of a HE PPDU using BCC encoding.

FIG. 14 shows an example of a block diagram of a transmitter generatinga data field of a HE PPDU using LDPC encoding.

FIG. 15 illustrates a 1×HE-STF tone in a per-channel PPDU transmissionaccording to the present embodiment.

FIG. 16 shows an example in which data is duplicated for each 40 MHzwhen transmitting an 80 MHz PPDU.

FIG. 17 is a diagram illustrating a tone plan of an 80 MHz band definedin 802.11be.

FIG. 18 is a flowchart illustrating the operation of the transmittingapparatus/device according to the present embodiment.

FIG. 19 is a flowchart illustrating the operation of the receivingapparatus/device according to the present embodiment.

FIG. 20 is a flow diagram illustrating a procedure for a transmittingSTA to transmit a PPDU according to the present embodiment.

FIG. 21 is a flow diagram illustrating a procedure for a receiving STAto receive a PPDU according to the present embodiment.

DETAILED DESCRIPTION

In the present specification, “A or B” may mean “only A”, “only B” or“both A and B”. In other words, in the present specification, “A or B”may be interpreted as “A and/or B”. For example, in the presentspecification, “A, B, or C” may mean “only A”, “only B”, “only C”, or“any combination of A, B, C”.

A slash (/) or comma used in the present specification may mean“and/or”. For example, “A/B” may mean “A and/or B”. Accordingly, “A/B”may mean “only A”, “only B”, or “both A and B”. For example, “A, B, C”may mean “A, B, or C”.

In the present specification, “at least one of A and B” may mean “onlyA”, “only B”, or “both A and B”. In addition, in the presentspecification, the expression “at least one of A or B” or “at least oneof A and/or B” may be interpreted as “at least one of A and B”.

In addition, in the present specification, “at least one of A, B, and C”may mean “only A”, “only B”, “only C”, or “any combination of A, B, andC”. In addition, “at least one of A, B, or C” or “at least one of A, B,and/or C” may mean “at least one of A, B, and C”.

In addition, a parenthesis used in the present specification may mean“for example”. Specifically, when indicated as “control information(EHT-signal)”, it may denote that “EHT-signal” is proposed as an exampleof the “control information”. In other words, the “control information”of the present specification is not limited to “EHT-signal”, and“EHT-signal” may be proposed as an example of the “control information”.In addition, when indicated as “control information (i.e., EHT-signal)”,it may also mean that “EHT-signal” is proposed as an example of the“control information”.

Technical features described individually in one figure in the presentspecification may be individually implemented, or may be simultaneouslyimplemented.

The following example of the present specification may be applied tovarious wireless communication systems. For example, the followingexample of the present specification may be applied to a wireless localarea network (WLAN) system. For example, the present specification maybe applied to the IEEE 802.11a/g/n/ac standard or the IEEE 802.11axstandard. In addition, the present specification may also be applied tothe newly proposed EHT standard or IEEE 802.11be standard. In addition,the example of the present specification may also be applied to a newWLAN standard enhanced from the EHT standard or the IEEE 802.11bestandard. In addition, the example of the present specification may beapplied to a mobile communication system. For example, it may be appliedto a mobile communication system based on long term evolution (LTE)depending on a 3^(rd) generation partnership project (3GPP) standard andbased on evolution of the LTE. In addition, the example of the presentspecification may be applied to a communication system of a 5G NRstandard based on the 3GPP standard.

Hereinafter, in order to describe a technical feature of the presentspecification, a technical feature applicable to the presentspecification will be described.

FIG. 1 shows an example of a transmitting apparatus and/or receivingapparatus of the present specification.

In the example of FIG. 1 , various technical features described belowmay be performed. FIG. 1 relates to at least one station (STA). Forexample, STAs 110 and 120 of the present specification may also becalled in various terms such as a mobile terminal, a wireless device, awireless transmit/receive unit (WTRU), a user equipment (UE), a mobilestation (MS), a mobile subscriber unit, or simply a user. The STAs 110and 120 of the present specification may also be called in various termssuch as a network, a base station, a node-B, an access point (AP), arepeater, a router, a relay, or the like. The STAs 110 and 120 of thepresent specification may also be referred to as various names such as areceiving apparatus, a transmitting apparatus, a receiving STA, atransmitting STA, a receiving device, a transmitting device, or thelike.

For example, the STAs 110 and 120 may serve as an AP or a non-AP. Thatis, the STAs 110 and 120 of the present specification may serve as theAP and/or the non-AP.

The STAs 110 and 120 of the present specification may support variouscommunication standards together in addition to the IEEE 802.11standard. For example, a communication standard (e.g., LTE, LTE-A, 5G NRstandard) or the like based on the 3GPP standard may be supported. Inaddition, the STA of the present specification may be implemented asvarious devices such as a mobile phone, a vehicle, a personal computer,or the like. In addition, the STA of the present specification maysupport communication for various communication services such as voicecalls, video calls, data communication, and self-driving(autonomous-driving), or the like.

The STAs 110 and 120 of the present specification may include a mediumaccess control (MAC) conforming to the IEEE 802.11 standard and aphysical layer interface for a radio medium.

The STAs 110 and 120 will be described below with reference to asub-figure (a) of FIG. 1 .

The first STA 110 may include a processor 111, a memory 112, and atransceiver 113. The illustrated process, memory, and transceiver may beimplemented individually as separate chips, or at least twoblocks/functions may be implemented through a single chip.

The transceiver 113 of the first STA performs a signaltransmission/reception operation. Specifically, an IEEE 802.11 packet(e.g., IEEE 802.11a/b/g/n/ac/ax/be, etc.) may be transmitted/received.

For example, the first STA 110 may perform an operation intended by anAP. For example, the processor 111 of the AP may receive a signalthrough the transceiver 113, process a reception (RX) signal, generate atransmission (TX) signal, and provide control for signal transmission.The memory 112 of the AP may store a signal (e.g., RX signal) receivedthrough the transceiver 113, and may store a signal (e.g., TX signal) tobe transmitted through the transceiver.

For example, the second STA 120 may perform an operation intended by anon-AP STA. For example, a transceiver 123 of a non-AP performs a signaltransmission/reception operation. Specifically, an IEEE 802.11 packet(e.g., IEEE 802.11a/b/g/n/ac/ax/be packet, etc.) may betransmitted/received.

For example, a processor 121 of the non-AP STA may receive a signalthrough the transceiver 123, process an RX signal, generate a TX signal,and provide control for signal transmission. A memory 122 of the non-APSTA may store a signal (e.g., RX signal) received through thetransceiver 123, and may store a signal (e.g., TX signal) to betransmitted through the transceiver.

For example, an operation of a device indicated as an AP in thespecification described below may be performed in the first STA 110 orthe second STA 120. For example, if the first STA 110 is the AP, theoperation of the device indicated as the AP may be controlled by theprocessor 111 of the first STA 110, and a related signal may betransmitted or received through the transceiver 113 controlled by theprocessor 111 of the first STA 110. In addition, control informationrelated to the operation of the AP or a TX/RX signal of the AP may bestored in the memory 112 of the first STA 110. In addition, if thesecond STA 120 is the AP, the operation of the device indicated as theAP may be controlled by the processor 121 of the second STA 120, and arelated signal may be transmitted or received through the transceiver123 controlled by the processor 121 of the second STA 120. In addition,control information related to the operation of the AP or a TX/RX signalof the AP may be stored in the memory 122 of the second STA 120.

For example, in the specification described below, an operation of adevice indicated as a non-AP (or user-STA) may be performed in the firstSTA 110 or the second STA 120. For example, if the second STA 120 is thenon-AP, the operation of the device indicated as the non-AP may becontrolled by the processor 121 of the second STA 120, and a relatedsignal may be transmitted or received through the transceiver 123controlled by the processor 121 of the second STA 120. In addition,control information related to the operation of the non-AP or a TX/RXsignal of the non-AP may be stored in the memory 122 of the second STA120. For example, if the first STA 110 is the non-AP, the operation ofthe device indicated as the non-AP may be controlled by the processor111 of the first STA 110, and a related signal may be transmitted orreceived through the transceiver 113 controlled by the processor 111 ofthe first STA 110. In addition, control information related to theoperation of the non-AP or a TX/RX signal of the non-AP may be stored inthe memory 112 of the first STA 110.

In the specification described below, a device called a(transmitting/receiving) STA, a first STA, a second STA, a STA1, a STA2,an AP, a first AP, a second AP, an AP1, an AP2, a(transmitting/receiving) terminal, a (transmitting/receiving) device, a(transmitting/receiving) apparatus, a network, or the like may imply theSTAs 110 and 120 of FIG. 1 . For example, a device indicated as, withouta specific reference numeral, the (transmitting/receiving) STA, thefirst STA, the second STA, the STA1, the STA2, the AP, the first AP, thesecond AP, the AP1, the AP2, the (transmitting/receiving) terminal, the(transmitting/receiving) device, the (transmitting/receiving) apparatus,the network, or the like may imply the STAs 110 and 120 of FIG. 1 . Forexample, in the following example, an operation in which various STAstransmit/receive a signal (e.g., a PPDU) may be performed in thetransceivers 113 and 123 of FIG. 1 . In addition, in the followingexample, an operation in which various STAs generate a TX/RX signal orperform data processing and computation in advance for the TX/RX signalmay be performed in the processors 111 and 121 of FIG. 1 . For example,an example of an operation for generating the TX/RX signal or performingthe data processing and computation in advance may include: 1) anoperation ofdetermining/obtaining/configuring/computing/decoding/encoding bitinformation of a sub-field (SIG, STF, LTF, Data) included in a PPDU; 2)an operation of determining/configuring/obtaining a time resource orfrequency resource (e.g., a subcarrier resource) or the like used forthe sub-field (SIG, STF, LTF, Data) included the PPDU; 3) an operationof determining/configuring/obtaining a specific sequence (e.g., a pilotsequence, an STF/LTF sequence, an extra sequence applied to SIG) or thelike used for the sub-field (SIG, STF, LTF, Data) field included in thePPDU; 4) a power control operation and/or power saving operation appliedfor the STA; and 5) an operation related todetermining/obtaining/configuring/decoding/encoding or the like of anACK signal. In addition, in the following example, a variety ofinformation used by various STAs fordetermining/obtaining/configuring/computing/decoding/decoding a TX/RXsignal (e.g., information related to a field/subfield/controlfield/parameter/power or the like) may be stored in the memories 112 and122 of FIG. 1 .

The aforementioned device/STA of the sub-figure (a) of FIG. 1 may bemodified as shown in the sub-figure (b) of FIG. 1 . Hereinafter, theSTAs 110 and 120 of the present specification will be described based onthe sub-figure (b) of FIG. 1 .

For example, the transceivers 113 and 123 illustrated in the sub-figure(b) of FIG. 1 may perform the same function as the aforementionedtransceiver illustrated in the sub-figure (a) of FIG. 1 . For example,processing chips 114 and 124 illustrated in the sub-figure (b) of FIG. 1may include the processors 111 and 121 and the memories 112 and 122. Theprocessors 111 and 121 and memories 112 and 122 illustrated in thesub-figure (b) of FIG. 1 may perform the same function as theaforementioned processors 111 and 121 and memories 112 and 122illustrated in the sub-figure (a) of FIG. 1 .

A mobile terminal, a wireless device, a wireless transmit/receive unit(WTRU), a user equipment (UE), a mobile station (MS), a mobilesubscriber unit, a user, a user STA, a network, a base station, aNode-B, an access point (AP), a repeater, a router, a relay, a receivingunit, a transmitting unit, a receiving STA, a transmitting STA, areceiving device, a transmitting device, a receiving apparatus, and/or atransmitting apparatus, which are described below, may imply the STAs110 and 120 illustrated in the sub-figure (a)/(b) of FIG. 1 , or mayimply the processing chips 114 and 124 illustrated in the sub-figure (b)of FIG. 1 . That is, a technical feature of the present specificationmay be performed in the STAs 110 and 120 illustrated in the sub-figure(a)/(b) of FIG. 1 , or may be performed only in the processing chips 114and 124 illustrated in the sub-figure (b) of FIG. 1 . For example, atechnical feature in which the transmitting STA transmits a controlsignal may be understood as a technical feature in which a controlsignal generated in the processors 111 and 121 illustrated in thesub-figure (a)/(b) of FIG. 1 is transmitted through the transceivers 113and 123 illustrated in the sub-figure (a)/(b) of FIG. 1 . Alternatively,the technical feature in which the transmitting STA transmits thecontrol signal may be understood as a technical feature in which thecontrol signal to be transferred to the transceivers 113 and 123 isgenerated in the processing chips 114 and 124 illustrated in thesub-figure (b) of FIG. 1 .

For example, a technical feature in which the receiving STA receives thecontrol signal may be understood as a technical feature in which thecontrol signal is received by means of the transceivers 113 and 123illustrated in the sub-figure (a) of FIG. 1 . Alternatively, thetechnical feature in which the receiving STA receives the control signalmay be understood as the technical feature in which the control signalreceived in the transceivers 113 and 123 illustrated in the sub-figure(a) of FIG. 1 is obtained by the processors 111 and 121 illustrated inthe sub-figure (a) of FIG. 1 . Alternatively, the technical feature inwhich the receiving STA receives the control signal may be understood asthe technical feature in which the control signal received in thetransceivers 113 and 123 illustrated in the sub-figure (b) of FIG. 1 isobtained by the processing chips 114 and 124 illustrated in thesub-figure (b) of FIG. 1 .

Referring to the sub-figure (b) of FIG. 1 , software codes 115 and 125may be included in the memories 112 and 122. The software codes 115 and126 may include instructions for controlling an operation of theprocessors 111 and 121. The software codes 115 and 125 may be includedas various programming languages.

The processors 111 and 121 or processing chips 114 and 124 of FIG. 1 mayinclude an application-specific integrated circuit (ASIC), otherchipsets, a logic circuit and/or a data processing device. The processormay be an application processor (AP). For example, the processors 111and 121 or processing chips 114 and 124 of FIG. 1 may include at leastone of a digital signal processor (DSP), a central processing unit(CPU), a graphics processing unit (GPU), and a modulator and demodulator(modem). For example, the processors 111 and 121 or processing chips 114and 124 of FIG. 1 may be SNAPDRAGON™ series of processors made byQualcomm®, EXYNOS™ series of processors made by Samsung®, A series ofprocessors made by Apple®, HELIO™ series of processors made byMediaTek®, ATOM™ series of processors made by Intel® or processorsenhanced from these processors.

In the present specification, an uplink may imply a link forcommunication from a non-AP STA to an SP STA, and an uplinkPPDU/packet/signal or the like may be transmitted through the uplink. Inaddition, in the present specification, a downlink may imply a link forcommunication from the AP STA to the non-AP STA, and a downlinkPPDU/packet/signal or the like may be transmitted through the downlink.

FIG. 2 is a conceptual view illustrating the structure of a wirelesslocal area network (WLAN).

An upper part of FIG. 2 illustrates the structure of an infrastructurebasic service set (BSS) of institute of electrical and electronicengineers (IEEE) 802.11.

Referring the upper part of FIG. 2 , the wireless LAN system may includeone or more infrastructure BSSs 200 and 205 (hereinafter, referred to asBSS). The BSSs 200 and 205 as a set of an AP and a STA such as an accesspoint (AP) 225 and a station (STA1) 200-1 which are successfullysynchronized to communicate with each other are not concepts indicatinga specific region. The BSS 205 may include one or more STAs 205-1 and205-2 which may be joined to one AP 230.

The BSS may include at least one STA, APs providing a distributionservice, and a distribution system (DS) 210 connecting multiple APs.

The distribution system 210 may implement an extended service set (ESS)240 extended by connecting the multiple BSSs 200 and 205. The ESS 240may be used as a term indicating one network configured by connectingone or more APs 225 or 230 through the distribution system 210. The APincluded in one ESS 240 may have the same service set identification(SSID).

A portal 220 may serve as a bridge which connects the wireless LANnetwork (IEEE 802.11) and another network (e.g., 802.X).

In the BSS illustrated in the upper part of FIG. 2 , a network betweenthe APs 225 and 230 and a network between the APs 225 and 230 and theSTAs 200-1, 205-1, and 205-2 may be implemented. However, the network isconfigured even between the STAs without the APs 225 and 230 to performcommunication. A network in which the communication is performed byconfiguring the network even between the STAs without the APs 225 and230 is defined as an Ad-Hoc network or an independent basic service set(IBSS).

A lower part of FIG. 2 illustrates a conceptual view illustrating theIBSS.

Referring to the lower part of FIG. 2 , the IBSS is a BSS that operatesin an Ad-Hoc mode. Since the IBSS does not include the access point(AP), a centralized management entity that performs a managementfunction at the center does not exist. That is, in the IBSS, STAs 250-1,250-2, 250-3, 255-4, and 255-5 are managed by a distributed manner. Inthe IBSS, all STAs 250-1, 250-2, 250-3, 255-4, and 255-5 may beconstituted by movable STAs and are not permitted to access the DS toconstitute a self-contained network.

FIG. 3 illustrates a general link setup process.

In S310, a STA may perform a network discovery operation. The networkdiscovery operation may include a scanning operation of the STA. Thatis, to access a network, the STA needs to discover a participatingnetwork. The STA needs to identify a compatible network beforeparticipating in a wireless network, and a process of identifying anetwork present in a particular area is referred to as scanning.Scanning methods include active scanning and passive scanning.

FIG. 3 illustrates a network discovery operation including an activescanning process. In active scanning, a STA performing scanningtransmits a probe request frame and waits for a response to the proberequest frame in order to identify which AP is present around whilemoving to channels. A responder transmits a probe response frame as aresponse to the probe request frame to the STA having transmitted theprobe request frame. Here, the responder may be a STA that transmits thelast beacon frame in a BSS of a channel being scanned. In the BSS, sincean AP transmits a beacon frame, the AP is the responder. In an IBSS,since STAs in the IBSS transmit a beacon frame in turns, the responderis not fixed. For example, when the STA transmits a probe request framevia channel 1 and receives a probe response frame via channel 1, the STAmay store BSS-related information included in the received proberesponse frame, may move to the next channel (e.g., channel 2), and mayperform scanning (e.g., transmits a probe request and receives a proberesponse via channel 2) by the same method.

Although not shown in FIG. 3 , scanning may be performed by a passivescanning method. In passive scanning, a STA performing scanning may waitfor a beacon frame while moving to channels. A beacon frame is one ofmanagement frames in IEEE 802.11 and is periodically transmitted toindicate the presence of a wireless network and to enable the STAperforming scanning to find the wireless network and to participate inthe wireless network. In a BSS, an AP serves to periodically transmit abeacon frame. In an IBSS, STAs in the IBSS transmit a beacon frame inturns. Upon receiving the beacon frame, the STA performing scanningstores information related to a BSS included in the beacon frame andrecords beacon frame information in each channel while moving to anotherchannel. The STA having received the beacon frame may store BSS-relatedinformation included in the received beacon frame, may move to the nextchannel, and may perform scanning in the next channel by the samemethod.

After discovering the network, the STA may perform an authenticationprocess in S320. The authentication process may be referred to as afirst authentication process to be clearly distinguished from thefollowing security setup operation in S340. The authentication processin S320 may include a process in which the STA transmits anauthentication request frame to the AP and the AP transmits anauthentication response frame to the STA in response. The authenticationframes used for an authentication request/response are managementframes.

The authentication frames may include information related to anauthentication algorithm number, an authentication transaction sequencenumber, a status code, a challenge text, a robust security network(RSN), and a finite cyclic group.

The STA may transmit the authentication request frame to the AP. The APmay determine whether to allow the authentication of the STA based onthe information included in the received authentication request frame.The AP may provide the authentication processing result to the STA viathe authentication response frame.

When the STA is successfully authenticated, the STA may perform anassociation process in S330. The association process includes a processin which the STA transmits an association request frame to the AP andthe AP transmits an association response frame to the STA in response.The association request frame may include, for example, informationrelated to various capabilities, a beacon listen interval, a service setidentifier (SSID), a supported rate, a supported channel, RSN, amobility domain, a supported operating class, a traffic indication map(TIM) broadcast request, and an interworking service capability. Theassociation response frame may include, for example, information relatedto various capabilities, a status code, an association ID (AID), asupported rate, an enhanced distributed channel access (EDCA) parameterset, a received channel power indicator (RCPI), a receivedsignal-to-noise indicator (RSNI), a mobility domain, a timeout interval(association comeback time), an overlapping BSS scanning parameter, aTIM broadcast response, and a QoS map.

In S340, the STA may perform a security setup process. The securitysetup process in S340 may include a process of setting up a private keythrough four-way handshaking, for example, through an extensibleauthentication protocol over LAN (EAPOL) frame.

FIG. 4 illustrates an example of a PPDU used in an IEEE standard.

As illustrated, various types of PHY protocol data units (PPDUs) areused in IEEE a/g/n/ac standards. Specifically, an LTF and a STF includea training signal, a SIG-A and a SIG-B include control information for areceiving STA, and a data field includes user data corresponding to aPSDU (MAC PDU/aggregated MAC PDU).

FIG. 4 also includes an example of an HE PPDU according to IEEE 802.1lax. The HE PPDU according to FIG. 4 is an illustrative PPDU formultiple users. An HE-SIG-B may be included only in a PPDU for multipleusers, and an HE-SIG-B may be omitted in a PPDU for a single user.

As illustrated in FIG. 4 , the HE-PPDU for multiple users (MUs) mayinclude a legacy-short training field (L-STF), a legacy-long trainingfield (L-LTF), a legacy-signal (L-SIG), a high efficiency-signal A(HE-SIG A), a high efficiency-signal-B (HE-SIG B), a highefficiency-short training field (HE-STF), a high efficiency-longtraining field (HE-LTF), a data field (alternatively, an MAC payload),and a packet extension (PE) field. The respective fields may betransmitted for illustrated time periods (i.e., 4 or 8 μs).

Hereinafter, a resource unit (RU) used for a PPDU is described. An RUmay include a plurality of subcarriers (or tones). An RU may be used totransmit a signal to a plurality of STAs according to OFDMA. Further, anRU may also be defined to transmit a signal to one STA. An RU may beused for an STF, an LTF, a data field, or the like.

FIG. 5 illustrates a layout of resource units (RUs) used in a band of 20MHz.

As illustrated in FIG. 5 , resource units (RUs) corresponding todifferent numbers of tones (i.e., subcarriers) may be used to form somefields of an HE-PPDU. For example, resources may be allocated inillustrated RUs for an HE-STF, an HE-LTF, and a data field.

As illustrated in the uppermost part of FIG. 5 , a 26-unit (i.e., a unitcorresponding to 26 tones) may be disposed. Six tones may be used for aguard band in the leftmost band of the 20 MHz band, and five tones maybe used for a guard band in the rightmost band of the 20 MHz band.Further, seven DC tones may be inserted in a center band, that is, a DCband, and a 26-unit corresponding to 13 tones on each of the left andright sides of the DC band may be disposed. A 26-unit, a 52-unit, and a106-unit may be allocated to other bands. Each unit may be allocated fora receiving STA, that is, a user.

The layout of the RUs in FIG. 5 may be used not only for a multipleusers (MUs) but also for a single user (SU), in which case one 242-unitmay be used and three DC tones may be inserted as illustrated in thelowermost part of FIG. 5 .

Although FIG. 5 proposes RUs having various sizes, that is, a 26-RU, a52-RU, a 106-RU, and a 242-RU, specific sizes of RUs may be extended orincreased. Therefore, the present embodiment is not limited to thespecific size of each RU (i.e., the number of corresponding tones).

FIG. 6 illustrates a layout of RUs used in a band of 40 MHz.

Similarly to FIG. 5 in which RUs having various sizes are used, a 26-RU,a 52-RU, a 106-RU, a 242-RU, a 484-RU, and the like may be used in anexample of FIG. 6 . Further, five DC tones may be inserted in a centerfrequency, 12 tones may be used for a guard band in the leftmost band ofthe 40 MHz band, and 11 tones may be used for a guard band in therightmost band of the 40 MHz band.

As illustrated in FIG. 6 , when the layout of the RUs is used for asingle user, a 484-RU may be used. The specific number of RUs may bechanged similarly to FIG. 5 .

FIG. 7 illustrates a layout of RUs used in a band of 80 MHz.

Similarly to FIG. 5 and FIG. 6 in which RUs having various sizes areused, a 26-RU, a 52-RU, a 106-RU, a 242-RU, a 484-RU, a 996-RU, and thelike may be used in an example of FIG. 7 . Further, seven DC tones maybe inserted in the center frequency, 12 tones may be used for a guardband in the leftmost band of the 80 MHz band, and 11 tones may be usedfor a guard band in the rightmost band of the 80 MHz band. In addition,a 26-RU corresponding to 13 tones on each of the left and right sides ofthe DC band may be used.

As illustrated in FIG. 7 , when the layout of the RUs is used for asingle user, a 996-RU may be used, in which case five DC tones may beinserted.

The RU described in the present specification may be used in uplink (UL)communication and downlink (DL) communication. For example, when UL-MUcommunication which is solicited by a trigger frame is performed, atransmitting STA (e.g., an AP) may allocate a first RU (e.g.,26/52/106/242-RU, etc.) to a first STA through the trigger frame, andmay allocate a second RU (e.g., 26/52/106/242-RU, etc.) to a second STA.Thereafter, the first STA may transmit a first trigger-based PPDU basedon the first RU, and the second STA may transmit a second trigger-basedPPDU based on the second RU. The first/second trigger-based PPDU istransmitted to the AP at the same (or overlapped) time period.

For example, when a DL MU PPDU is configured, the transmitting STA(e.g., AP) may allocate the first RU (e.g., 26/52/106/242-RU. etc.) tothe first STA, and may allocate the second RU (e.g., 26/52/106/242-RU,etc.) to the second STA. That is, the transmitting STA (e.g., AP) maytransmit HE-STF, HE-LTF, and Data fields for the first STA through thefirst RU in one MU PPDU, and may transmit HE-STF, HE-LTF, and Datafields for the second STA through the second RU.

Information related to a layout of the RU may be signaled throughHE-SIG-B.

FIG. 8 illustrates a structure of an HE-SIG-B field.

As illustrated, an HE-SIG-B field 810 includes a common field 820 and auser-specific field 830. The common field 820 may include informationcommonly applied to all users (i.e., user STAs) which receive SIG-B. Theuser-specific field 830 may be called a user-specific control field.When the SIG-B is transferred to a plurality of users, the user-specificfield 830 may be applied only any one of the plurality of users.

As illustrated in FIG. 8 , the common field 820 and the user-specificfield 830 may be separately encoded.

The common field 820 may include RU allocation information of N*8 bits.For example, the RU allocation information may include informationrelated to a location of an RU. For example, when a 20 MHz channel isused as shown in FIG. 5 , the RU allocation information may includeinformation related to a specific frequency band to which a specific RU(26-RU/52-RU/106-RU) is arranged.

An example of a case in which the RU allocation information consists of8 bits is as follows.

TABLE 1 8 bits indices Number (B7 B6 B5 B4 of B3 B2 B1 B0) #1 #2 #3 #4#5 #6 #7 #8 #9 entries 00000000 26 26 26 26 26 26 26 26 26 1 00000001 2626 26 26 26 26 26 52 1 00000010 26 26 26 26 26 52 26 26 1 00000011 26 2626 26 26 52 52 1 00000100 26 26 52 26 26 26 26 26 1 00000101 26 26 52 2626 26 52 1 00000110 26 26 52 26 52 26 26 1 00000111 26 26 52 26 52 52 100001000 52 26 26 26 26 26 26 26 1

As shown the example of FIG. 5 , up to nine 26-RUs may be allocated tothe 20 MHz channel. When the RU allocation information of the commonfield 820 is set to “00000000” as shown in Table 1, the nine 26-RUs maybe allocated to a corresponding channel (i.e., 20 MHz). In addition,when the RU allocation information of the common field 820 is set to“00000001” as shown in Table 1, seven 26-RUs and one 52-RU are arrangedin a corresponding channel. That is, in the example of FIG. 5 , the52-RU may be allocated to the rightmost side, and the seven 26-RUs maybe allocated to the left thereof.

The example of Table 1 shows only some of RU locations capable ofdisplaying the RU allocation information.

For example, the RU allocation information may include an example ofTable 2 below.

TABLE 2 8 bits indices Number (B7 B6 B5 B4 of 83 B2 B1 B0) #1 #2 #3 #4#5 #6 #7 #8 #9 entries 01000y₂y₁y₀ 106 26 26 26 26 26 8 01001y₂y₁y₀ 10626 26 26 52 8

“01000y2y1y0” relates to an example in which a 106-RU is allocated tothe leftmost side of the 20 MHz channel, and five 26-RUs are allocatedto the right side thereof. In this case, a plurality of STAs (e.g.,user-STAs) may be allocated to the 106-RU, based on a MU-MIMO scheme.Specifically, up to 8 STAs (e.g., user-STAs) may be allocated to the106-RU, and the number of STAs (e.g., user-STAs) allocated to the 106-RUis determined based on 3-bit information (y2y1y0). For example, when the3-bit information (y2y1y0) is set to N, the number of STAs (e.g.,user-STAs) allocated to the 106-RU based on the MU-MIMO scheme may beN+1.

In general, a plurality of STAs (e.g., user STAs) different from eachother may be allocated to a plurality of RUs. However, the plurality ofSTAs (e.g., user STAs) may be allocated to one or more RUs having atleast a specific size (e.g., 106 subcarriers), based on the MU-MIMOscheme.

As shown in FIG. 8 , the user-specific field 830 may include a pluralityof user fields. As described above, the number of STAs (e.g., user STAs)allocated to a specific channel may be determined based on the RUallocation information of the common field 820. For example, when the RUallocation information of the common field 820 is “00000000”, one userSTA may be allocated to each of nine 26-RUs (e.g., nine user STAs may beallocated). That is, up to 9 user STAs may be allocated to a specificchannel through an OFDMA scheme. In other words, up to 9 user STAs maybe allocated to a specific channel through a non-MU-MIMO scheme.

For example, when RU allocation is set to “01000y2y1y0”, a plurality ofSTAs may be allocated to the 106-RU arranged at the leftmost sidethrough the MU-MIMO scheme, and five user STAs may be allocated to five26-RUs arranged to the right side thereof through the non-MU MIMOscheme. This case is specified through an example of FIG. 9 .

FIG. 9 illustrates an example in which a plurality of user STAs areallocated to the same RU through a MU-MIMO scheme.

For example, when RU allocation is set to “01000010” as shown in FIG. 9, a 106-RU may be allocated to the leftmost side of a specific channel,and five 26-RUs may be allocated to the right side thereof. In addition,three user STAs may be allocated to the 106-RU through the MU-MIMOscheme. As a result, since eight user STAs are allocated, theuser-specific field 830 of HE-SIG-B may include eight user fields.

The eight user fields may be expressed in the order shown in FIG. 9 . Inaddition, as shown in FIG. 8 , two user fields may be implemented withone user block field.

The user fields shown in FIG. 8 and FIG. 9 may be configured based ontwo formats. That is, a user field related to a MU-MIMO scheme may beconfigured in a first format, and a user field related to a non-MIMOscheme may be configured in a second format. Referring to the example ofFIG. 9 , a user field 1 to a user field 3 may be based on the firstformat, and a user field 4 to a user field 8 may be based on the secondformat. The first format or the second format may include bitinformation of the same length (e.g., 21 bits).

Each user field may have the same size (e.g., 21 bits). For example, theuser field of the first format (the first of the MU-MIMO scheme) may beconfigured as follows.

For example, a first bit (i.e., B0-B10) in the user field (i.e., 21bits) may include identification information (e.g., STA-ID, partial AID,etc.) of a user STA to which a corresponding user field is allocated. Inaddition, a second bit (i.e., B11-B14) in the user field (i.e., 21 bits)may include information related to a spatial configuration.

In addition, a third bit (i.e., B15-18) in the user field (i.e., 21bits) may include modulation and coding scheme (MCS) information. TheMCS information may be applied to a data field in a PPDU includingcorresponding SIG-B.

An MCS, MCS information, an MCS index, an MCS field, or the like used inthe present specification may be indicated by an index value. Forexample, the MCS information may be indicated by an index 0 to an index11. The MCS information may include information related to aconstellation modulation type (e.g., BPSK, QPSK, 16-QAM, 64-QAM,256-QAM, 1024-QAM, etc.) and information related to a coding rate (e.g.,1/2, 2/3, 3/4, 5/6e, etc.). Information related to a channel coding type(e.g., LCC or LDPC) may be excluded in the MCS information.

In addition, a fourth bit (i.e., B19) in the user field (i.e., 21 bits)may be a reserved field.

In addition, a fifth bit (i.e., B20) in the user field (i.e., 21 bits)may include information related to a coding type (e.g., BCC or LDPC).That is, the fifth bit (i.e., B20) may include information related to atype (e.g., BCC or LDPC) of channel coding applied to the data field inthe PPDU including the corresponding SIG-B.

The aforementioned example relates to the user field of the first format(the format of the MU-MIMO scheme). An example of the user field of thesecond format (the format of the non-MU-MIMO scheme) is as follows.

A first bit (e.g., B0-B10) in the user field of the second format mayinclude identification information of a user STA. In addition, a secondbit (e.g., B11-B13) in the user field of the second format may includeinformation related to the number of spatial streams applied to acorresponding RU. In addition, a third bit (e.g., B14) in the user fieldof the second format may include information related to whether abeamforming steering matrix is applied. A fourth bit (e.g., B15-B18) inthe user field of the second format may include modulation and codingscheme (MCS) information. In addition, a fifth bit (e.g., B19) in theuser field of the second format may include information related towhether dual carrier modulation (DCM) is applied. In addition, a sixthbit (i.e., B20) in the user field of the second format may includeinformation related to a coding type (e.g., BCC or LDPC).

Hereinafter, a PPDU transmitted/received in a STA of the presentspecification will be described.

FIG. 10 illustrates an example of a PPDU used in the presentspecification.

The PPDU of FIG. 10 may be called in various terms such as an EHT PPDU,a TX PPDU, an RX PPDU, a first type or N-th type PPDU, or the like. Forexample, in the present specification, the PPDU or the EHT PPDU may becalled in various terms such as a TX PPDU, a RX PPDU, a first type orN-th type PPDU, or the like. In addition, the EHT PPDU may be used in anEHT system and/or a new WLAN system enhanced from the EHT system.

The PPDU of FIG. 10 may indicate the entirety or part of a PPDU typeused in the EHT system. For example, the example of FIG. 10 may be usedfor both of a single-user (SU) mode and a multi-user (MU) mode. In otherwords, the PPDU of FIG. 10 may be a PPDU for one receiving STA or aplurality of receiving STAs. When the PPDU of FIG. 10 is used for atrigger-based (TB) mode, the EHT-SIG of FIG. 10 may be omitted. In otherwords, an STA which has received a trigger frame for uplink-MU (UL-MU)may transmit the PPDU in which the EHT-SIG is omitted in the example ofFIG. 10 .

In FIG. 10 , an L-STF to an EHT-LTF may be called a preamble or aphysical preamble, and may begenerated/transmitted/received/obtained/decoded in a physical layer.

A subcarrier spacing of the L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, andEHT-SIG fields of FIG. 10 may be determined as 312.5 kHz, and asubcarrier spacing of the EHT-STF, EHT-LTF, and Data fields may bedetermined as 78.125 kHz. That is, a tone index (or subcarrier index) ofthe L-STF, L-LTF, L-SIG, RL-SIG, U-SIG, and EHT-SIG fields may beexpressed in unit of 312.5 kHz, and a tone index (or subcarrier index)of the EHT-STF, EHT-LTF, and Data fields may be expressed in unit of78.125 kHz.

In the PPDU of FIG. 10 , the L-LTE and the L-STF may be the same asthose in the conventional fields.

The L-SIG field of FIG. 10 may include, for example, bit information of24 bits. For example, the 24-bit information may include a rate field of4 bits, a reserved bit of 1 bit, a length field of 12 bits, a parity bitof 1 bit, and a tail bit of 6 bits. For example, the length field of 12bits may include information related to a length or time duration of aPPDU. For example, the length field of 12 bits may be determined basedon a type of the PPDU. For example, when the PPDU is a non-HT, HT, VHTPPDU or an EHT PPDU, a value of the length field may be determined as amultiple of 3. For example, when the PPDU is an HE PPDU, the value ofthe length field may be determined as “a multiple of 3”+1 or “a multipleof 3”+2. In other words, for the non-HT, HT, VHT PPDI or the EHT PPDU,the value of the length field may be determined as a multiple of 3, andfor the HE PPDU, the value of the length field may be determined as “amultiple of 3”+1 or “a multiple of 3”+2.

For example, the transmitting STA may apply BCC encoding based on a 1/2coding rate to the 24-bit information of the L-SIG field. Thereafter,the transmitting STA may obtain a BCC coding bit of 48 bits. BPSKmodulation may be applied to the 48-bit coding bit, thereby generating48 BPSK symbols. The transmitting STA may map the 48 BPSK symbols topositions except for a pilot subcarrier{subcarrier index −21, −7, +7,+21} and a DC subcarrier{subcarrier index 0}. As a result, the 48 BPSKsymbols may be mapped to subcarrier indices −26 to −22, −20 to −8, −6 to−1, +1 to +6, +8 to +20, and +22 to +26. The transmitting STA mayadditionally map a signal of {−1, −1, −1, 1} to a subcarrier index {−28,−27, +27, +28}. The aforementioned signal may be used for channelestimation on a frequency domain corresponding to {−28, −27, +27, +28}.

The transmitting STA may generate an RL-SIG generated in the same manneras the L-SIG. BPSK modulation may be applied to the RL-SIG. Thereceiving STA may know that the RX PPDU is the HE PPDU or the EHT PPDU,based on the presence of the RL-SIG.

A universal SIG (U-SIG) may be inserted after the RL-SIG of FIG. 10 .The U-SIB may be called in various terms such as a first SIG field, afirst SIG, a first type SIG, a control signal, a control signal field, afirst (type) control signal, or the like.

The U-SIG may include information of N bits, and may include informationfor identifying a type of the EHT PPDU. For example, the U-SIG may beconfigured based on two symbols (e.g., two contiguous OFDM symbols).Each symbol (e.g., OFDM symbol) for the U-SIG may have a duration of 4μs. Each symbol of the U-SIG may be used to transmit the 26-bitinformation. For example, each symbol of the U-SIG may betransmitted/received based on 52 data tomes and 4 pilot tones.

Through the U-SIG (or U-SIG field), for example, A-bit information(e.g., 52 un-coded bits) may be transmitted. A first symbol of the U-SIGmay transmit first X-bit information (e.g., 26 un-coded bits) of theA-bit information, and a second symbol of the U-SIB may transmit theremaining Y-bit information (e.g. 26 un-coded bits) of the A-bitinformation. For example, the transmitting STA may obtain 26 un-codedbits included in each U-SIG symbol. The transmitting STA may performconvolutional encoding (i.e., BCC encoding) based on a rate of R=1/2 togenerate 52-coded bits, and may perform interleaving on the 52-codedbits. The transmitting STA may perform BPSK modulation on theinterleaved 52-coded bits to generate 52 BPSK symbols to be allocated toeach U-SIG symbol. One U-SIG symbol may be transmitted based on 65 tones(subcarriers) from a subcarrier index −28 to a subcarrier index +28,except for a DC index 0. The 52 BPSK symbols generated by thetransmitting STA may be transmitted based on the remaining tones(subcarriers) except for pilot tones, i.e., tones −21, −7, +7, +21.

For example, the A-bit information (e.g., 52 un-coded bits) generated bythe U-SIG may include a CRC field (e.g., a field having a length of 4bits) and a tail field (e.g., a field having a length of 6 bits). TheCRC field and the tail field may be transmitted through the secondsymbol of the U-SIG. The CRC field may be generated based on 26 bitsallocated to the first symbol of the U-SIG and the remaining 16 bitsexcept for the CRC/tail fields in the second symbol, and may begenerated based on the conventional CRC calculation algorithm. Inaddition, the tail field may be used to terminate trellis of aconvolutional decoder, and may be set to, for example, “000000”.

The A-bit information (e.g., 52 un-coded bits) transmitted by the U-SIG(or U-SIG field) may be divided into version-independent bits andversion-dependent bits. For example, the version-independent bits mayhave a fixed or variable size. For example, the version-independent bitsmay be allocated only to the first symbol of the U-SIG, or theversion-independent bits may be allocated to both of the first andsecond symbols of the U-SIG. For example, the version-independent bitsand the version-dependent bits may be called in various terms such as afirst control bit, a second control bit, or the like.

For example, the version-independent bits of the U-SIG may include a PHYversion identifier of 3 bits. For example, the PHY version identifier of3 bits may include information related to a PHY version of a TX/RX PPDU.For example, a first value of the PHY version identifier of 3 bits mayindicate that the TX/RX PPDU is an EHT PPDU. In other words, when thetransmitting STA transmits the EHT PPDU, the PHY version identifier of 3bits may be set to a first value. In other words, the receiving STA maydetermine that the RX PPDU is the EHT PPDU, based on the PHY versionidentifier having the first value.

For example, the version-independent bits of the U-SIG may include aUL/DL flag field of 1 bit. A first value of the UL/DL flag field of 1bit relates to UL communication, and a second value of the UL/DL flagfield relates to DL communication.

For example, the version-independent bits of the U-SIG may includeinformation related to a TXOP length and information related to a BSScolor ID.

For example, when the EHT PPDU is divided into various types (e.g.,various types such as an EHT PPDU related to an SU mode, an EHT PPDUrelated to a MU mode, an EHT PPDU related to a TB mode, an EHT PPDUrelated to extended range transmission, or the like), informationrelated to the type of the EHT PPDU may be included in theversion-dependent bits of the U-SIG.

For example, the U-SIG may include: 1) a bandwidth field includinginformation related to a bandwidth; 2) a field including informationrelated to an MCS scheme applied to EHT-SIG; 3) an indication fieldincluding information regarding whether a dual subcarrier modulation(DCM) scheme is applied to EHT-SIG; 4) a field including informationrelated to the number of symbol used for EHT-SIG; 5) a field includinginformation regarding whether the EHT-SIG is generated across a fullband; 6) a field including information related to a type of EHT-LTF/STF;and 7) information related to a field indicating an EHT-LTF length and aCP length.

Preamble puncturing may be applied to the PPDU of FIG. 10 . The preamblepuncturing implies that puncturing is applied to part (e.g., a secondary20 MHz band) of the full band. For example, when an 80 MHz PPDU istransmitted, an STA may apply puncturing to the secondary 20 MHz bandout of the 80 MHz band, and may transmit a PPDU only through a primary20 MHz band and a secondary 40 MHz band.

For example, a pattern of the preamble puncturing may be configured inadvance. For example, when a first puncturing pattern is applied,puncturing may be applied only to the secondary 20 MHz band within the80 MHz band. For example, when a second puncturing pattern is applied,puncturing may be applied to only any one of two secondary 20 MHz bandsincluded in the secondary 40 MHz band within the 80 MHz band. Forexample, when a third puncturing pattern is applied, puncturing may beapplied to only the secondary 20 MHz band included in the primary 80 MHzband within the 160 MHz band (or 80+80 MHz band). For example, when afourth puncturing is applied, puncturing may be applied to at least one20 MHz channel not belonging to a primary 40 MHz band in the presence ofthe primary 40 MHz band included in the 80 MHz band within the 160 MHzband (or 80+80 MHz band).

Information related to the preamble puncturing applied to the PPDU maybe included in U-SIG and/or EHT-SIG. For example, a first field of theU-SIG may include information related to a contiguous bandwidth, andsecond field of the U-SIG may include information related to thepreamble puncturing applied to the PPDU.

For example, the U-SIG and the EHT-SIG may include the informationrelated to the preamble puncturing, based on the following method. Whena bandwidth of the PPDU exceeds 80 MHz, the U-SIG may be configuredindividually in unit of 80 MHz. For example, when the bandwidth of thePPDU is 160 MHz, the PPDU may include a first U-SIG for a first 80 MHzband and a second U-SIG for a second 80 MHz band. In this case, a firstfield of the first U-SIG may include information related to a 160 MHzbandwidth, and a second field of the first U-SIG may include informationrelated to a preamble puncturing (i.e., information related to apreamble puncturing pattern) applied to the first 80 MHz band. Inaddition, a first field of the second U-SIG may include informationrelated to a 160 MHz bandwidth, and a second field of the second U-SIGmay include information related to a preamble puncturing (i.e.,information related to a preamble puncturing pattern) applied to thesecond 80 MHz band. Meanwhile, an EHT-SIG contiguous to the first U-SIGmay include information related to a preamble puncturing applied to thesecond 80 MHz band (i.e., information related to a preamble puncturingpattern), and an EHT-SIG contiguous to the second U-SIG may includeinformation related to a preamble puncturing (i.e., information relatedto a preamble puncturing pattern) applied to the first 80 MHz band.

Additionally or alternatively, the U-SIG and the EHT-SIG may include theinformation related to the preamble puncturing, based on the followingmethod. The U-SIG may include information related to a preamblepuncturing (i.e., information related to a preamble puncturing pattern)for all bands. That is, the EHT-SIG may not include the informationrelated to the preamble puncturing, and only the U-SIG may include theinformation related to the preamble puncturing (i.e., the informationrelated to the preamble puncturing pattern).

The U-SIG may be configured in unit of 20 MHz. For example, when an 80MHz PPDU is configured, the U-SIG may be duplicated. That is, fouridentical U-SIGs may be included in the 80 MHz PPDU. PPDUs exceeding an80 MHz bandwidth may include different U-SIGs.

The EHT-SIG of FIG. 10 may include control information for the receivingSTA. The EHT-SIG may be transmitted through at least one symbol, and onesymbol may have a length of 4 μs. Information related to the number ofsymbols used for the EHT-SIG may be included in the U-SIG.

The EHT-SIG may include a technical feature of the HE-SIG-B describedwith reference to FIG. 8 and FIG. 9 . For example, the EHT-SIG mayinclude a common field and a user-specific field as in the example ofFIG. 8 . The common field of the EHT-SIG may be omitted, and the numberof user-specific fields may be determined based on the number of users.

As in the example of FIG. 8 , the common field of the EHT-SIG and theuser-specific field of the EHT-SIG may be individually coded. One userblock field included in the user-specific field may include informationfor two users, but a last user block field included in the user-specificfield may include information for one user. That is, one user blockfield of the EHT-SIG may include up to two user fields. As in theexample of FIG. 9 , each user field may be related to MU-MIMOallocation, or may be related to non-MU-MIMO allocation.

As in the example of FIG. 8 , the common field of the EHT-SIG mayinclude a CRC bit and a tail bit. A length of the CRC bit may bedetermined as 4 bits. A length of the tail bit may be determined as 6bits, and may be set to ‘000000’.

As in the example of FIG. 8 , the common field of the EHT-SIG mayinclude RU allocation information. The RU allocation information mayimply information related to a location of an RU to which a plurality ofusers (i.e., a plurality of receiving STAs) are allocated. The RUallocation information may be configured in unit of 8 bits (or N bits),as in Table 1.

A mode in which the common field of the EHT-SIG is omitted may besupported. The mode in the common field of the EHT-SIG is omitted may becalled a compressed mode. When the compressed mode is used, a pluralityof users (i.e., a plurality of receiving STAs) may decode the PPDU(e.g., the data field of the PPDU), based on non-OFDMA. That is, theplurality of users of the EHT PPDU may decode the PPDU (e.g., the datafield of the PPDU) received through the same frequency band. Meanwhile,when a non-compressed mode is used, the plurality of users of the EHTPPDU may decode the PPDU (e.g., the data field of the PPDU), based onOFDMA. That is, the plurality of users of the EHT PPDU may receive thePPDU (e.g., the data field of the PPDU) through different frequencybands.

The EHT-SIG may be configured based on various MCS schemes. As describedabove, information related to an MCS scheme applied to the EHT-SIG maybe included in U-SIG. The EHT-SIG may be configured based on a DCMscheme. For example, among N data tones (e.g., 52 data tones) allocatedfor the EHT-SIG, a first modulation scheme may be applied to half ofconsecutive tones, and a second modulation scheme may be applied to theremaining half of the consecutive tones. That is, a transmitting STA mayuse the first modulation scheme to modulate specific control informationthrough a first symbol and allocate it to half of the consecutive tones,and may use the second modulation scheme to modulate the same controlinformation by using a second symbol and allocate it to the remaininghalf of the consecutive tones. As described above, information (e.g., a1-bit field) regarding whether the DCM scheme is applied to the EHT-SIGmay be included in the U-SIG. An HE-STF of FIG. 10 may be used forimproving automatic gain control estimation in a multiple input multipleoutput (MIMO) environment or an OFDMA environment. An HE-LTF of FIG. 10may be used for estimating a channel in the MIMO environment or theOFDMA environment.

The EHT-STF of FIG. 10 may be set in various types. For example, a firsttype of STF (e.g., 1×STF) may be generated based on a first type STFsequence in which a non-zero coefficient is arranged with an interval of16 subcarriers. An STF signal generated based on the first type STFsequence may have a period of 0.8 μs, and a periodicity signal of 0.8 μsmay be repeated 5 times to become a first type STF having a length of 4μs. For example, a second type of STF (e.g., 2×STF) may be generatedbased on a second type STF sequence in which a non-zero coefficient isarranged with an interval of 8 subcarriers. An STF signal generatedbased on the second type STF sequence may have a period of 1.6 μs, and aperiodicity signal of 1.6 μs may be repeated 5 times to become a secondtype STF having a length of 8 μs. Hereinafter, an example of a sequencefor configuring an EHT-STF (i.e., an EHT-STF sequence) is proposed. Thefollowing sequence may be modified in various ways.

The EHT-STF may be configured based on the following sequence M.M={−1,−1,−1,1,1,1,−1,1,1,1,−1,1,1,−1,1}  <Equation 1>

The EHT-STF for the 20 MHz PPDU may be configured based on the followingequation. The following example may be a first type (i.e., 1×STF)sequence. For example, the first type sequence may be included in not atrigger-based (TB) PPDU but an EHT-PPDU. In the following equation,(a:b:c) may imply a duration defined as b tone intervals (i.e., asubcarrier interval) from atone index (i.e., subcarrier index) ‘a’ toatone index ‘c’. For example, the equation 2 below may represent asequence defined as 16 tone intervals from a tone index −112 to a toneindex 112. Since a subcarrier spacing of 78.125 kHz is applied to theEHT-STR, the 16 tone intervals may imply that an EHT-STF coefficient (orelement) is arranged with an interval of 78.125*16=1250 kHz. Inaddition, * implies multiplication, and sqrt( ) implies a square root.In addition, j implies an imaginary number.EHT-STF(−112:16:112)={M}*(1+j)/sqrt(2)  <Equation 2>

EHT-STF(0)=0

The EHT-STF for the 40 MHz PPDU may be configured based on the followingequation. The following example may be the first type (i.e., 1×STF)sequence.EHT-STF(−240:16:240)={M,0,−M}*(1+j)/sqrt(2)  <Equation 3>

The EHT-STF for the 80 MHz PPDU may be configured based on the followingequation. The following example may be the first type (i.e., 1×STF)sequence.EHT-STF(−496:16:496)={M,1,−M,0,−M,1,−M}*(1+j)/sqrt(2)  <Equation 4>

The EHT-STF for the 160 MHz PPDU may be configured based on thefollowing equation. The following example may be the first type (i.e.,1×STF) sequence.EHT-STF(−1008:16:1008)={M,1,−M,0,−M,1,−M,0,−M,−1,M,0,−M,1,−M}*(1+j)/sqrt(2)  <Equation5>

In the EHT-STF for the 80+80 MHz PPDU, a sequence for lower 80 MHz maybe identical to Equation 4. In the EHT-STF for the 80+80 MHz PPDU, asequence for upper 80 MHz may be configured based on the followingequation.EHT-STF(−496:16:496)={−M,−1,M,0,−M,1,−M}*(1+j)/sqrt(2)  <Equation 6>

Equation 7 to Equation 11 below relate to an example of a second type(i.e., 2×STF) sequence.EHT-STF(−120:8:120)={M,0,−M}*(1+j)/sqrt(2)  <Equation 7>

The EHT-STF for the 40 MHz PPDU may be configured based on the followingequation.EHT-STF(−248:8:248)={M,−1,−M,0,M,−1,M}*(1+j)/sqrt(2)  <Equation 8>

EHT-STF(−248)=0

EHT-STF(248)=0

The EHT-STF for the 80 MHz PPDU may be configured based on the followingequation.EHT-STF(−504:8:504)={M,−1,M,−1,−M,−1,M,0,−M,1,M,1,−M,1,−M}*(1+j)/sqrt(2)  <Equation9>

The EHT-STF for the 160 MHz PPDU may be configured based on thefollowing equation.EHT-STF(−1016:16:1016)={M,−1,M,−1,−M,−1,M,0,−M,1,M,1,−M,1,−M,0,−M,1,−M,1,M,1,−M,0,−M,1,M,1,−M,1,−M}*(1+j)/sqrt(2)  <Equation10>

EHT-STF(−8)=0, EHT-STF(8)=0,

EHT-STF(−1016)=0, EHT-STF(1016)=0

In the EHT-STF for the 80+80 MHz PPDU, a sequence for lower 80 MHz maybe identical to Equation 9. In the EHT-STF for the 80+80 MHz PPDU, asequence for upper 80 MHz may be configured based on the followingequation.EHT-STF(−504:8:504)={−M,1,−M,1,M,1,−M,0,−M,1,M,1,−M,1,−M}*(1+j)/sqrt(2)  <Equation11>

EHT-STF(−504)=0,

EHT-STF(504)=0

The EHT-LTF may have first, second, and third types (i.e., 1×, 2×,4×LTF). For example, the first/second/third type LTF may be generatedbased on an LTF sequence in which a non-zero coefficient is arrangedwith an interval of 4/2/1 subcarriers. The first/second/third type LTFmay have a time length of 3.2/6.4/12.8 μs. In addition, a GI (e.g.,0.8/1/6/3.2 μs) having various lengths may be applied to thefirst/second/third type LTF.

Information related to a type of STF and/or LTF (information related toa GI applied to LTF is also included) may be included in a SIG-A fieldand/or SIG-B field or the like of FIG. 10 .

A PPDU (e.g., EHT-PPDU) of FIG. 10 may be configured based on theexample of FIG. 5 and FIG. 6 .

For example, an EHT PPDU transmitted on a 20 MHz band, i.e., a 20 MHzEHT PPDU, may be configured based on the RU of FIG. 5 . That is, alocation of an RU of EHT-STF, EHT-LTF, and data fields included in theEHT PPDU may be determined as shown in FIG. 5 .

An EHT PPDU transmitted on a 40 MHz band, i.e., a 40 MHz EHT PPDU, maybe configured based on the RU of FIG. 6 . That is, a location of an RUof EHT-STF, EHT-LTF, and data fields included in the EHT PPDU may bedetermined as shown in FIG. 6 .

Since the RU location of FIG. 6 corresponds to 40 MHz, a tone-plan for80 MHz may be determined when the pattern of FIG. 6 is repeated twice.That is, an 80 MHz EHT PPDU may be transmitted based on a new tone-planin which not the RU of FIG. 7 but the RU of FIG. 6 is repeated twice.

When the pattern of FIG. 6 is repeated twice, 23 tones (i.e., 11 guardtones+12 guard tones) may be configured in a DC region. That is, atone-plan for an 80 MHz EHT PPDU allocated based on OFDMA may have 23 DCtones. Unlike this, an 80 MHz EHT PPDU allocated based on non-OFDMA(i.e., a non-OFDMA full bandwidth 80 MHz PPDU) may be configured basedon a 996-RU, and may include 5 DC tones, 12 left guard tones, and 11right guard tones.

A tone-plan for 160/240/320 MHz may be configured in such a manner thatthe pattern of FIG. 6 is repeated several times.

The PPDU of FIG. 10 may be determined (or identified) as an EHT PPDUbased on the following method.

A receiving STA may determine a type of an RX PPDU as the EHT PPDU,based on the following aspect. For example, the RX PPDU may bedetermined as the EHT PPDU: 1) when a first symbol after an L-LTF signalof the RX PPDU is a BPSK symbol; 2) when RL-SIG in which the L-SIG ofthe RX PPDU is repeated is detected; and 3) when a result of applying“modulo 3” to a value of a length field of the L-SIG of the RX PPDU isdetected as “0”. When the RX PPDU is determined as the EHT PPDU, thereceiving STA may detect a type of the EHT PPDU (e.g., anSU/MU/Trigger-based/Extended Range type), based on bit informationincluded in a symbol after the RL-SIG of FIG. 10 . In other words, thereceiving STA may determine the RX PPDU as the EHT PPDU, based on: 1) afirst symbol after an L-LTF signal, which is a BPSK symbol; 2) RL-SIGcontiguous to the L-SIG field and identical to L-SIG; 3) L-SIG includinga length field in which a result of applying “modulo 3” is set to “0”;and 4) a 3-bit PHY version identifier of the aforementioned U-SIG (e.g.,a PHY version identifier having a first value).

For example, the receiving STA may determine the type of the RX PPDU asthe EHT PPDU, based on the following aspect. For example, the RX PPDUmay be determined as the HE PPDU: 1) when a first symbol after an L-LTFsignal is a BPSK symbol; 2) when RL-SIG in which the L-SIG is repeatedis detected; and 3) when a result of applying “modulo 3” to a value of alength field of the L-SIG is detected as “1” or “2”.

For example, the receiving STA may determine the type of the RX PPDU asa non-HT, HT, and VHT PPDU, based on the following aspect. For example,the RX PPDU may be determined as the non-HT, HT, and VHT PPDU: 1) when afirst symbol after an L-LTF signal is a BPSK symbol; and 2) when RL-SIGin which L-SIG is repeated is not detected. In addition, even if thereceiving STA detects that the RL-SIG is repeated, when a result ofapplying “modulo 3” to the length value of the L-SIG is detected as “0”,the RX PPDU may be determined as the non-HT, HT, and VHT PPDU.

In the following example, a signal represented as a (TX/RX/UL/DL)signal, a (TX/RX/UL/DL) frame, a (TX/RX/UL/DL) packet, a (TX/RX/UL/DL)data unit, (TX/RX/UL/DL) data, or the like may be a signaltransmitted/received based on the PPDU of FIG. 10 . The PPDU of FIG. 10may be used to transmit/receive frames of various types. For example,the PPDU of FIG. 10 may be used for a control frame. An example of thecontrol frame may include a request to send (RTS), a clear to send(CTS), a power save-poll (PS-poll), BlockACKReq, BlockAck, a null datapacket (NDP) announcement, and a trigger frame. For example, the PPDU ofFIG. 10 may be used for a management frame. An example of the managementframe may include a beacon frame, a (re-)association request frame, a(re-)association response frame, a probe request frame, and a proberesponse frame. For example, the PPDU of FIG. 10 may be used for a dataframe. For example, the PPDU of FIG. 10 may be used to simultaneouslytransmit at least two or more of the control frames, the managementframe, and the data frame.

FIG. 11 illustrates an example of a modified transmission device and/orreceiving device of the present specification.

Each device/STA of the sub-figure (a)/(b) of FIG. 1 may be modified asshown in FIG. 11 . A transceiver 630 of FIG. 11 may be identical to thetransceivers 113 and 123 of FIG. 1 . The transceiver 630 of FIG. 11 mayinclude a receiver and a transmitter.

A processor 610 of FIG. 11 may be identical to the processors 111 and121 of FIG. 1 . Alternatively, the processor 610 of FIG. 11 may beidentical to the processing chips 114 and 124 of FIG. 1 .

A memory 620 of FIG. 11 may be identical to the memories 112 and 122 ofFIG. 1 . Alternatively, the memory 620 of FIG. 11 may be a separateexternal memory different from the memories 112 and 122 of FIG. 1 .

Referring to FIG. 11 , a power management module 611 manages power forthe processor 610 and/or the transceiver 630. A battery 612 suppliespower to the power management module 611. A display 613 outputs a resultprocessed by the processor 610. A keypad 614 receives inputs to be usedby the processor 610. The keypad 614 may be displayed on the display613. A SIM card 615 may be an integrated circuit which is used tosecurely store an international mobile subscriber identity (IMSI) andits related key, which are used to identify and authenticate subscriberson mobile telephony devices such as mobile phones and computers.

Referring to FIG. 11 , a speaker 640 may output a result related to asound processed by the processor 610. A microphone 641 may receive aninput related to a sound to be used by the processor 610.

1. Tone Plan in 802.11ax WLAN System

In the present specification, a tone plan relates to a rule fordetermining a size of a resource unit (RU) and/or a location of the RU.Hereinafter, a PPDU based on the IEEE 802.11ax standard, that is, a toneplan applied to an HE PPDU, will be described. In other words,hereinafter, the RU size and RU location applied to the HE PPDU aredescribed, and control information related to the RU applied to the HEPPDU is described.

In the present specification, control information related to an RU (orcontrol information related to a tone plan) may include a size andlocation of the RU, information of a user STA allocated to a specificRU, a frequency bandwidth for a PPDU in which the RU is included, and/orcontrol information on a modulation scheme applied to the specific RU.The control information related to the RU may be included in an SIGfield. For example, in the IEEE 802.11ax standard, the controlinformation related to the RU is included in an HE-SIG-B field. That is,in a process of generating a TX PPDU, a transmitting STA may allow thecontrol information on the RU included in the PPDU to be included in theHE-SIG-B field. In addition, a receiving STA may receive an HE-SIG-Bincluded in an RX PPDU and obtain control information included in theHE-SIG-B, so as to determine whether there is an RU allocated to thereceiving STA and decode the allocated RU, based on the HE-SIG-B.

In the IEEE 802.11ax standard, HE-STF, HE-LTF, and data fields may beconfigured in unit of RUs. That is, when a first RU for a firstreceiving STA is configured, STF/LTF/data fields for the first receivingSTA may be transmitted/received through the first RU.

In the IEEE 802.11ax standard, a PPDU (i.e., SU PPDU) for one receivingSTA and a PPDU (i.e., MU PPDU) for a plurality of receiving STAs areseparately defined, and respective tone plans are separately defined.Specific details will be described below.

The RU defined in 11ax may include a plurality of subcarriers. Forexample, when the RU includes N subcarriers, it may be expressed by anN-tone RU or N RUs. A location of a specific RU may be expressed by asubcarrier index. The subcarrier index may be defined in unit of asubcarrier frequency spacing. In the 11ax standard, the subcarrierfrequency spacing is 312.5 kHz or 78.125 kHz, and the subcarrierfrequency spacing for the RU is 78.125 kHz. That is, a subcarrier index+1 for the RU may mean a location which is more increased by 78.125 kHzthan a DC tone, and a subcarrier index −1 for the RU may mean a locationwhich is more decreased by 78.125 kHz than the DC tone. For example,when the location of the specific RU is expressed by [−121:−96], the RUmay be located in a region from a subcarrier index −121 to a subcarrierindex −96. As a result, the RU may include 26 subcarriers.

The N-tone RU may include a pre-set pilot tone.

2. Null Subcarrier and Pilot Subcarrier

A subcarrier and resource allocation in the 802.11ax system will bedescribed.

An OFDM symbol consists of subcarriers, and the number of subcarriersmay function as a bandwidth of a PPDU. In the WLAN 802.11 system, a datasubcarrier used for data transmission, a pilot subcarrier used for phaseinformation and parameter tacking, and an unused subcarrier not used fordata transmission and pilot transmission are defined.

An HE MU PPDU which uses OFDMA transmission may be transmitted by mixinga 26-tone RU, a 52-tone RU, a 106-tone RU, a 242-tone RU, a 484-tone RU,and a 996-tone RU.

Herein, the 26-tone RU consists of 24 data subcarriers and 2 pilotsubcarriers. The 52-tone RU consists of 48 data subcarriers and 4 pilotsubcarriers. The 106-tone RU consists of 102 data subcarriers and 4pilot subcarriers. The 242-tone RU consists of 234 data subcarriers and8 pilot subcarriers. The 484-tone RU consists of 468 data subcarriersand 16 pilot subcarriers. The 996-tone RU consists of 980 datasubcarriers and 16 pilot subcarriers.

1) Null Subcarrier

As shown in FIG. 5 to FIG. 7 , a null subcarrier exists between 26-toneRU, 52-tone RU, and 106-tone RU locations. The null subcarrier islocated near a DC or edge tone to protect against transmit centerfrequency leakage, receiver DC offset, and interference from an adjacentRU. The null subcarrier has zero energy. An index of the null subcarrieris listed as follows.

Channel Width RU Size Null Subcarrier Indices 20 MHz 26, 52 ±69, ±122106 none 242 none 40 MHz 26, 52 ±3, ±56, ±57, ±110, ±137, ±190, ±191,±244 106 ±3,±110, ±137, ±244 242, 484 none 80 MHz 26, 52 ±17, ±70, ±71,±124, ±151, ±204, ±205, ±258, ±259, ±312, ±313, ±366, ±393, ±446, ±447,±500 106 ±17, ±124, ±151, ±258, ±259, ±366, ±393, ±500 242, 484 none 996none 160 MHZ  26, 52, 106 {null subcarrier indices in 80 MHz − 512, nullsubcarrier indices in 80 MHz ± 512} 242, 484, none 996, 2 × 996

A null subcarrier location for each 80 MHz frequency segment of the80+80 MHz HE PPDU shall follow the location of the 80 MHz HE PPDU.

2) Pilot Subcarrier

If a pilot subcarrier exists in an HE-LTF field of HE SU PPDU, HE MUPPDU, HE ER SU PPDU, or HE TB PPDU, a location of a pilot sequence in anHE-LTF field and data field may be the same as a location of 4×HE-LTF.In 1×HE-LTF, the location of the pilot sequence in HE-LTF is configuredbased on pilot subcarriers for a data field multiplied 4 times. If thepilot subcarrier exists in 2×HE-LTF, the location of the pilotsubcarrier shall be the same as a location of a pilot in a 4× datasymbol. All pilot subcarriers are located at even-numbered indiceslisted below.

Channel Width RU Size: Pilot Subcarrier Indices 20 MHz 26, 52 ±10, ±22,±36, ±48, ±62, ±76, ±90, ±102, ±116 106, 242 ±22, ±48, ±90, ±116 40 MHz26, 52 ±10, ±24, ±36, ±50, ±64, ±78, ±90, ±104, ±116, ±130, ±144, ±158,±170, ±184, ±198, ±212, ±224, ±238 106, 242, ±10, ±36, ±78, ±104, ±144,±170, ±212, 484 ±238 80 MHZ 26,52 ±10, ±24, ±38, ±50, ±64. ±78, ±92.±104. ±118, ±130, ±144, ±158, ±172, ±184, ±198, ±212, ±226, ±238, ±252,±266, ±280, ±292, ±306, ±320, ±334, ±346, ±360, ±372, ±386, ±400, ±414,±426, ±440, ±454, ±468, ±480, ±494 106, 242, ±24, ±50, ±92, ±118, ±158,±184, ±226, 484 ±252, ±266, ±292, ±334, ±360, ±400, ±426, ±468, ±494 996±24, ±92, ±158, ±226, ±266, ±334. ±400, ±468 160 MHz  26, 52, 106,{pilot subcarrier indices in 80 MHz − 512, 242, 484 pilot subcarrierindices in 80 MHz ± 512} 996 {for the lower 80 MHz, pilot subcarrierindices in 80 MHz − 512, for the upper 80 MHz, pilot subcarrier indicesin 80 MHz ± 512}

At 160 MHz or 80+80 MHz, the location of the pilot subcarrier shall usethe same 80 MHz location for 80 MHz of both sides.

3. HE Transmit Procedure and Constellation Mapping

In an 802.11ax wireless local area network (WLAN) system, transmissionprocedures (or transmit procedures) in a physical layer (PHY) include aprocedure for an HE Single User (SU) PPDU, a transmission procedure foran HE extended range (ER) SU PPDU, a transmission procedure for an HEMulti User (MU) PPDU, and a transmission procedure for an HEtrigger-based (TB) PPDU. A FORMAT field of aPHY-TXSTART.request(TXVECTOR) may be the same as HE_SU, HE_MU, HE_ER_SUor HE_TB. The transmission procedures do not describe operations ofoptional features, such as Dual Carrier Modulation (DCM). Among thediverse transmission procedures, FIG. 21 shows only the PHY transmissionprocedure for the HE SU PPDU.

FIG. 12 shows an example of a PHY transmission procedure for HE SU PPDU.

In order to transmit data, the MAC generates a PHY-TXSTART.requestprimitive, which causes a PHY entity to enter a transmit state.Additionally, the PHY is configured to operate in an appropriatefrequency via station management through PLME. Other transmissionparameters, such as HE-MCS, coding type, and transmission power areconfigured through a PHY-SAP by using a PHY-TXSTART.request(TXVECTOR)primitive. After transmitting a PPDU that transfers (or communicates) atrigger frame, a MAC sublayer may issue a PHY-TRIGGER.request togetherwith a TRIGVECTOR parameter, which provides information needed fordemodulating an HE TB PPDU response that is expected of the PHY entity.

The PHY indicates statuses of a primary channel and another channel viaPHY-CCA.indication. The transmission of a PPDU should be started by thePHY after receiving the PHY-TXSTART.request(TXVECTOR) primitive.

After a PHY preamble transmission is started, the PHY entity immediatelyinitiates data scrambling and data encoding. An encoding method for thedata field is based on FEC_CODING, CH_BANDWIDTH, NUM_STS, STBC, MCS, andNUM_USERS parameters of the TXVECTOR.

A SERVICE field and a PSDU are encoded in a transmitter (or transmittingdevice) block diagram, which will be described later on. Data should beexchanged between the MAC and the PHY through a PHY-DATA.request(DATA)primitive that is issued by the MAC and PHY-DATA.confirm primitives thatare issued by the PHY. A PHY padding bit is applied to the PSDU in orderto set a number of bits of the coded PSDU to be an integer multiple of anumber of coded bits per OFDM symbol.

The transmission is swiftly (or quickly) ended by the MAC through aPHY-TXEND.request primitive. The PSDU transmission is ended uponreceiving a PHY-TXEND.request primitive. Each PHY-TXEND.requestprimitive mat notify its reception together with a PHY-TXEND.confirmprimitive from the PHY.

A packet extension and/or a signal extension may exist in a PPDU. APHY-TXEND.confirm primitive is generated at an actual end time of a mostrecent PPDU, an end time of a packet extension, and an end time of asignal extension.

In the PHY, a Guard Interval (GI) that is indicated together with a GIduration in a GI_TYPE parameter of the TXVECTOR is inserted in all dataOFDM symbols as a solution for a delay spread.

If the PPDU transmission is completed, the PHY entity enters a receivestate.

In order to generate each field of the HE PPDU, the following blockdiagrams are used.

-   -   a) pre-FEC PHY padding    -   b) Scrambler    -   c) FEC (BCC or LDPC) encoders    -   d) post-FEC PHY padding    -   e) Stream parser    -   f) Segment parser (for contiguous 160 MHz and non-contiguous        80+80 MHz transmission)    -   g) BCC interleaver    -   h) Constellation mapper    -   i) DCM tone mapper    -   j) Pilot insertion    -   k) Replication over multiple 20 MHz (for BW>20 MHz)    -   l) Multiplication by 1st column of P_(HE-LTF)    -   m) LDPC tone mapper    -   n) Segment deparser    -   o) Space time block code (STBC) encoder for one spatial stream    -   p) Cyclic shift diversity (CSD) per STS insertion    -   q) Spatial mapper    -   r) Frequency mapping    -   s) Inverse discrete Fourier transform (IDFT)    -   f) Cyclic shift diversity (CSD) per chain insertion    -   u) Guard interval (GI) insertion    -   v) Windowing

FIG. 13 shows an example of a block diagram of a transmitter generatinga data field of a HE PPDU using BCC encoding.

FIG. 13 shows a block diagram of a transmitter used to generate the datafield of the HE PPDU to which binary convolution coding (BCC) encodingis applied and capable of UL transmission or DL non-MU MIMO transmissionin 26-tone RU, 52-tone RU, 106-tone RU, or 242-tone RU.

Referring to FIG. 13 , with respect to the bit stream input to thetransmitter block diagram, 1) Pre-FEC PHY padding is performed, 2)scrambling operation is performed, 3) BCC encoding is performed, and 4)Post-FEC PHY padding is performed, 5) a stream parsing operation formapping coded bits to a specific spatial stream is performed, 6) BCCinterleaving is performed for each spatial stream, 7) Constellationmapping is performed for each spatial stream, and a modulation symbolmay be generated.

The Dual Carrier Modulation (DCM) tone mapper, which is part of theconstellation mapper, is applied only when DCM is indicated for the RU.A subset of these transmitter block diagrams, consisting of theConstellation Mapper and CSD blocks, as well as the blocks to the rightof the spatial mapping blocks, are also used to generate HE-LTF fieldsor HE-STF fields.

FIG. 14 shows an example of a block diagram of a transmitter generatinga data field of a HE PPDU using LDPC encoding.

FIG. 14 shows a block diagram of a transmitter used to generate the datafield of the HE PPDU to which Low Density Parity Check (LDPC) encodingis applied and capable of UL transmission or DL non-MU MIMO transmissionin 26-tone RU, 52-tone RU, 106-tone RU, 242-tone RU, 484-tone RU, or996-tone RU.

Referring to FIG. 14 , with respect to the bit stream input to thetransmitter block diagram, 1) Pre-FEC PHY padding is performed, 2)scrambling operation is performed, 3) LDPC encoding is performed, and 4)Post-FEC PHY padding is performed, 5) a stream parsing operation formapping coded bits to a specific spatial stream is performed, 6)constellation mapping is performed for each spatial stream, 7) the LDPCtone mapping may be performed on modulation symbols generated based onthe constellation mapping.

The transmitter block diagram of FIG. 14 is also applied to the datafield of the HE MU PPDU and the data field of the HE TB PPDU transmittedin an RU allocated to one user (regardless of whether or not spatiallymultiplexed with another user). The DCM tone mapper, which is part ofthe constellation mapper, is applied only when DCM is indicated for theRU.

Since the transmitter block diagrams of FIGS. 13 and 14 do not have asegment parser, the above operations are performed for one frequencysegment. However, if necessary, segment parsing may be performed todivide frequency segments by adding a segment parser after the streamparser in the transmitter block diagrams of FIGS. 13 and 14 .Accordingly, the BCC interleaving, the constellation mapping, or theLDPC tone mapping may be performed for each frequency segment (for eachRU in Multi-RU).

In addition, in HE MU transmission, except that cyclic shift diversity(CSD) is performed with knowledge of the space-time stream start indexfor that user, the PPDU encoding processor uses Resource Unit (RU) isperformed independently. All user data of the RU is combined and mappedto the transmission chain of the spatial mapping block.

Constellation mapping will be described below.

Constellation mapping refers to mapping of input bits of theconstellation mapper and complex constellation points for binary phaseshift keying (BPSK), quadrature phase shift keying (QPSK), quadratureamplitude modulation (16-QAM), and 256-QAM. That is, the constellationmapper may map bits from an output of a stream parser or a segmentparser (if present) to complex constellation points according to amodulation scheme.

The DCM scheme may be applied only to a data field and/or SIG-B field ofan HE PPDU. Additionally, the DCM scheme may be used or may not be usedin the transmitting device (optional feature).

Amore detailed description of the DCM scheme of 11ax is as follows.

DCM is an optional modulation scheme for HE-SIG-B and data fields. DCMmay be applied to an HE SU PPDU and an HE ER SU PPDU. In an HE MU PPDUor HE TB PPDU, DCM may be applied to an RU that includes data for oneuser and cannot be applied to an RU that includes data for multipleusers.

DCM is applicable only for HE-MCS 0, 1, 3, and 4. DCM is applicable onlyfor N_(SS)=1 or N_(SS)=2 (In case of a single user RU in an HE MU PPDU,N_(SS),r,u=1 or N_(SS),r,u=2). DCM is not applicable together withMU-MIMO or STBC.

When DCM is used, a bit sequence is mapped to one symbol pair (d′_(k),d′_(q(k))′). In order to use a frequency diversity for a 996-tone RU ora smaller RU, k has a range of 0<=k<=N_(SD)−1, and q(k) has a range ofN_(SD)<=q(k)<=2N_(SD)−1. For a 2×996-tone RU, k has a range of0<=k<=N_(SD)/2−1, and q(k) has a range of N_(SD)/2<=q(k)<=N_(SD)−1. Inorder to maximize the frequency diversity, an index of a DCM subcarrierpair (k, q(k)) is q(k)=k+N_(SD) for a 996-tone RU or a smaller RU, andq(k)=k+N_(SD)/2 for a 2×996-tone RU. Herein, when DCM=1, N_(SD) is givena value of N_(SD). And, when DCM=0, N_(SD) is given a half value ofN_(SD).

A modulation bit having DCM applied thereto may be described as follows.

-   -   For BPSK modulation with DCM, the input stream is broken into        groups of N_(CBPS) or N_(CBPS,u) its (B₀, B₁, . . . , B_(N)        _(CPBS,u) ⁻¹). Each bit B_(k) is BPSK modulated to a sample        d_(k). This generates the samples for the lower half of the data        subcarriers. For the upper half of the subcarriers, the samples        are generated as d′_(k+N) _(SD) =d′_(k)×e^(j(k+N) ^(SD) ^()π),        k=0, 1, . . . . N_(SD)−1. The N_(SD) here refers to the N_(SD)        with DCM=1, which is half the value of N_(SD) with DCM=0.    -   For QPSK modulation with DCM, the input stream is broken into        groups of N_(CBPS) or N_(CBPS,u) bits (B₀, B₁, . . . , B_(N)        _(CBPS,u) ⁻¹) Each pair of bits (B_(2k), B_(2k+1)) is QPSK        modulated to a symbol d′_(k). This generates the constellation        points for the lower half the data subcarriers in the RU. For        the upper half of the data subcarriers in the RU, d′_(k+N) _(SD)        =conj(d′_(k)), where conj( ) represents the complex conjugate        operation. The N_(SD) here refers to the N_(SD) with DCM=1,        which is half the value of N_(SD) with DCM=0.    -   For 16-QAM modulation with DCM, the input stream is broken into        groups of N_(CBPS) or N_(CBPS,u) bits (B₀, B₁, . . . , B_(N)        _(CBPS,u) ⁻¹). A group of 4 bits (B₄, B_(4k+1), B_(4k−2),        B_(4k+3)) is 16-QAM modulated to a sample d′_(k) as described in        17.3.5.8 (Subcarrier modulation mapping). This is the sample on        subcarrier k in the lower half. In the upper half, the sample        d′_(k+N) _(SD) on subcarrier k+N_(SD) is obtained by 16-QAM        modulating a per-mutation of the bits (B_(4k), B_(4k+1),        B_(4k−2), B_(4k−3)). Specifically, d′_(k+N) _(SD) , is obtained        by applying the 16-QAM modulation procedure in 18.3.5.8 to the        bit group (B_(4k+1), B_(4k), B_(4k+3), B_(4k−2)). The N_(SD)        here refers to the N_(SD) with DCM=1, which is half the value of        N_(SD) with DCM=0.

Hereinafter, LDPC tone mapping will be described.

LDPC tone mapping should be performed in all LDPC-coded streams by usingan LDPC tone mapping distance parameter D_(TM). D_(TM) is a constant foreach bandwidth and is given a value for each band, as shown below. LDPCtone mapping should not be performed for an encoded stream by using BCC.

160 MHZ, Parameter 20 MHZ 40 MHZ 80 MHZ 80 + 80 MHZ D_(TM) 4 6 9 9

For a VHT PPDU transmission, LDPC tone mapping for an LDPC-coded streamrelated to a user u may be performed, as shown below, by substituting astream of complex numbers generated by a constellation mapper.

-   -   d″_(t(k), i, n, l, u)=d′_(k, i, n, l, u); k=0, 1, . . . ,        N_(SD)−1 for 20 MHz, 40 MHz, 80 MHz and 80+80 MHz;

${k = 0},1,\ldots,{\frac{N_{SD}}{2} - 1}$for 160 MHz:

-   -   i=1, . . . , N_(SS,u);    -   n=0, 1, . . . , N_(SYM)−1;    -   l=0 for 20 MHz, 40 MHz, and 80 MHz;    -   l=0, 1 for 160 MHz and 80+80 MHz;    -   u=0, . . . , N_(user)−1

where

${t(k)} = \left\{ \begin{matrix}{{{D_{TM}\left( {k{mod}\ \frac{N_{SD}}{D_{TM}}} \right)} + \left\lfloor \frac{k \cdot D_{TM}}{N_{SD}} \right\rfloor},} \\{{{D_{TM}\left( {k{mod}\ \frac{N_{SD}/2}{D_{TM}}} \right)} + \left\lfloor \frac{k \cdot D_{TM}}{N_{SD}/2} \right\rfloor},}\end{matrix} \right.$for 20 MHz, 40 MHz, 80 MHz, and 80+80 MHz for 160 MHz

As a result of the LDPC tone mapping operation, each of twoconsecutively generated complex constellation numbers d′_(k,i,n,l,u) andd′_(k+1,i,n,l,u) may be transmitted from two data tones, respectively,each data tone being spaced apart by at least D_(TM)−1. For example,d′_(k,i,n,l,u) may be transmitted from a first data tone,d′_(k+1,i,n,l,u) may be transmitted from a second data tone, and thefirst data tone and the second data tone may be spaced apart byD_(TM)−1. The aforementioned operation is the same as performingblock-interleaving on complex numbers d′_(0,i,n,l,u), . . . ,d′_(NSD−1,i,n,l,u) for variables i, n, and u by using a matrix having aD_(TM) row and a N_(SD)/D_(TM) column (for 20 MHz, 40 MHz, 80 MHz or80+80 MHz) or N_(SD)/2*D_(TM) column (for 160 MHz). At this point,d′_(0,i,n,l,u), . . . , d′_(NSD-1,i,n,l,u) are written row-wise in thematrix, and d′_(0,i,n,l,u), . . . , d_(NSD-1,i,n,l,u) are readcolumn-wise from the matrix.

LDPC tone mapping is separately performed for an upper 80 MHz and alower 80 MHz of a 160 MHz or 80+80 MHz transmission that is indicated byfrequency subblock index 1.

Since LDPC tone mapping is not performed for a BCC-coded stream, thefollowing equation may be applied to the BCC-coded stream.

-   -   d″_(k,i,n,l,u)=d′_(k,i,n,l,u); k=0, 1, . . . , N_(SD)−1 for 20        MHz, 40 MHz, 80 MHz and 80+80 MHz;

${k = 0},1,\ldots,{\frac{N_{SD}}{2} - 1}$for 160 MHz;

-   -   i=1, . . . , N_(SS,u);    -   n=0, 1, . . . , N_(SYM)−1;    -   l=0 for 20 MHz, 40 MHz, and 80 MHz;    -   l=0, 1 for 160 MHz and 80+80 MHz;    -   u=0, . . . , N_(user)−1

Additionally, LDPC tone mapping should be performed in all LDPC-codedstreams that are mapped to a resource unit (RU). LDPC tone mappingshould not be performed on a stream having used BCC. When DCM is appliedto an LDPC-coded stream, D_(TM_DCM) should be applied to both a lowerhalf data subcarrier of the RU and an upper half data subcarrier of theRU. LDPC tone mapping distance parameters D_(TM) and D_(TM_DCM) areconstant values for each of an RU size and another RU size,

RU Size (tones) Parameter 26 52 106 242 484 996 2 × 996 D_(TM) 1 3 6 912 20 20 D_(TM)_DCM 1 1 3 9 9 14 14

LDPC tone mapping distance parameters D_(TM) and D_(TM_DCM) are appliedto a frequency subblock 1=0 and frequency subblock 1=1, respectively.

For an HE PPDU without DCM, in an r-th RU, LDPC tone mapping for anLDPC-coded stream related to a user u may be performed, as shown below,by substituting a stream of complex numbers generated by a constellationmapper.

-   -   d″_(t(k), i, n, l, r, u)=d′_(k, i, n, l, r, u)

where

-   -   k={0, 1, . . . , N_(SD)−1 for a 26-, 52-, 106-, 242-, 484- and        996-tone RU/0, 1, . . . , N_(SD)/2−1 for a 2×996-tone RU    -   i=1, . . . , N_(SS, r, u)    -   n=0, 1, . . . , N_(SYM)−1    -   l={0 for a 26-, 52-, 106-, 242-, 484- and 996-tone RU/0, 1 for a        2×996-tone RU    -   u=0, . . . , N_(user, r)−1    -   r=0, . . . , N_(RU)−1    -   N_(SD) is the number of data tones in the r-th RU

${t(k)} = \left\{ \begin{matrix}{{{D_{TM}\left( {k{mod}\ \frac{N_{SD}}{D_{TM}}} \right)} + \left\lfloor \frac{k \cdot D_{TM}}{N_{SD}} \right\rfloor},} \\{{{D_{TM}\left( {k{mod}\ \frac{N_{SD}/2}{D_{TM}}} \right)} + \left\lfloor \frac{k \cdot D_{TM}}{N_{SD}/2} \right\rfloor},}\end{matrix} \right.$for a 26-, 52-, 106-, 242-, 484- and 996-tone RU for a 2×996-tone RU

For an HE PPDU having DCM applied in a Data field, in an r-th RU, LDPCtone mapping for an LDPC-coded stream related to a user u may beperformed, as shown below, by substituting a stream of complex numbersgenerated by a constellation mapper.

-   -   d″_(t(k), i, n, l, r, u)=d″_(k, i, n, l, r, u)

where

-   -   k={0, 1, . . . , 2N_(SD)−1 for a 26-, 52-, 106-, 242-, 484- and        996-tone RU/0, 1, . . . , N_(SD)−1 for a 2×996-tone RU    -   i=1, . . . , N_(SS, r, u)    -   n=0, 1, . . . , N_(SYM)−1    -   l={0 for a 26-, 52-, 106-, 242-, 484- and 996-tone RU/0, 1 for a        2×996-tone RU    -   u=0, . . . , N_(user, r)−1    -   r=0, . . . , N_(RU)−1    -   N_(SD) is the number of data tones in the r-th RU if DCM is        applied

For a 26-, 52-, 106-, 242-, 484- and 996-tone RU.

${t(k)} = \left\{ \begin{matrix}{{{D_{TM\_ DCM}\left( {k{mod}\ \frac{N_{SD}}{D_{TM\_ DCM}}} \right)} + \left\lfloor \frac{k \cdot D_{TM\_ DCM}}{N_{SD}} \right\rfloor},{{{for}{}k} < N_{SD}}} \\{{{D_{{TM}{DCM}}\left( {\left( {k - N_{SD}} \right){mod}\ \frac{N_{SD}}{D_{{TM}{DCM}}}} \right)} + \left\lfloor \frac{\left( {k - N_{SD}} \right) \cdot D_{TM\_ DCM}}{N_{SD}} \right\rfloor + N_{SD}},{{{for}{}k} \geq N_{SD}}}\end{matrix} \right.$ Fora2 × 996‐toneRU,${t(k)} = \left\{ \begin{matrix}{{{D_{TM\_ DCM}\left( {k{mod}\ \frac{N_{SD}/2}{D_{TM\_ DCM}}} \right)} + \left\lfloor \frac{k \cdot D_{TM\_ DCM}}{N_{SD}/2} \right\rfloor},{{{for}{}0} \leq k < {N_{SD}/2}}} \\{{{D_{{TM}{\_ DCM}}\left( {\left( {k - {N_{SD}/2}} \right){mod}\ \frac{N_{SD}/2}{D_{T{M\_ DCM}}}} \right)} + \left\lfloor \frac{\left( {k - {N_{SD}/2}} \right) \cdot D_{{TM}{DCM}}}{N_{SD}/2} \right\rfloor + {N_{SD}/2}},{{{for}{N_{SD}/2}} \leq k < N_{SD}}}\end{matrix} \right.$

D_(TM_DCM) is the LDPC tone mapping distance for the r-th RU if DCM isapplied.

An LDPC tone mapper for a 26-, 52-, 106-, 242-, 484- and 996-tone isdefined as one segment. LDPC tone mapping is separately performed forupper 80 MHz and lower 80 MHz frequency segments of a 2×996-tone RU thatis indicated by frequency subblock index 1.

Since LDPC tone mapping is not performed for a BCC-coded stream, thefollowing equation may be applied to the BCC-coded stream.

-   -   d″_(k, i, n, l, r, u)=d′_(k, i, n, l, r, u)

where

-   -   k={=0, 1, . . . , N_(SD)−1 for a 26-, 52-, 106-, 242-, 484- and        996-tone RU/0, 1, . . . , N_(SD)/2−1 for a 2×996-tone RU    -   i=1, . . . , N_(SS, r, u)    -   n=0, 1, . . . , N_(SYM)−1    -   l={0 for a 26-, 52-, 106-, 242-, 484- and 996-tone RU/0, 1 for a        2×996-tone RU    -   u=0, . . . , N_(user, r)−1    -   r=0, . . . , N_(RU)−1

4. STF Sequence (or STF Signal)

The main purpose of the HE-STF field is to improve automatic gaincontrol estimation in MIMO transmission.

FIG. 15 illustrates a 1×HE-STF tone in a per-channel PPDU transmissionaccording to the present disclosure. Most particularly, FIG. 15 shows anexample of an HE-STF tone (i.e., 16-tone sampling) having a periodicityof 0.8 μs in 20 MHz/40 MHz/80 MHz bandwidths. Accordingly, in FIG. 15 ,the HE-STF tones for each bandwidth (or channel) may be positioned at 16tone intervals.

In FIG. 15 , the x-axis represents the frequency domain. The numbers onthe x-axis represent the indexes of a tone, and the arrows representmapping of a value that is not equal to 0 (i.e., a non-zero value) tothe corresponding tone index.

Sub-drawing (a) illustrates an example of a 1×HE-STF tone in a 20 MHzPPDU transmission.

Referring to sub-drawing (a), in case an HE-STF sequence (i.e., 1×HE-STFsequence) for a periodicity of 0.8 μs is mapped to tones of a 20 MHzchannel, the 1×HE-STF sequence is mapped to tones having tone indexesthat are divisible by 16 (i.e., multiples of 16), among the tones havingtone indexes ranging from −112 to 112, and, then, 0 may be mapped to theremaining tones. More specifically, in a 20 MHz channel, among the toneshaving tone indexes ranging from −112 to 112, a 1×HE-STF tone may bepositioned at a tone index that is divisible by 16 excluding the DC.Accordingly, a total of 14 1×HE-STF tones having the 1×HE-STF sequencemapped thereto may exist in the 20 MHz channel.

Sub-drawing (b) illustrates an example of a 1×HE-STF tone in a 40 MHzPPDU transmission.

Referring to sub-drawing (b), in case an HE-STF sequence (i.e., 1×HE-STFsequence) for a periodicity of 0.8 μs is mapped to tones of a 40 MHzchannel, the 1×HE-STF sequence is mapped to tones having tone indexesthat are divisible by 16 (i.e., multiples of 16), among the tones havingtone indexes ranging from −240 to 240, and, then, 0 may be mapped to theremaining tones. More specifically, in a 40 MHz channel, among the toneshaving tone indexes ranging from −240 to 240, a 1×HE-STF tone may bepositioned at a tone index that is divisible by 16 excluding the DC.Accordingly, a total of 30 1×HE-STF tones having the 1×HE-STF sequencemapped thereto may exist in the 40 MHz channel.

Sub-drawing (c) illustrates an example of a 1×HE-STF tone in an 80 MHzPPDU transmission.

Referring to sub-drawing (c), in case an HE-STF sequence (i.e., 1×HE-STFsequence) for a periodicity of 0.8 μs is mapped to tones of an 80 MHzchannel, the 1×HE-STF sequence is mapped to tones having tone indexesthat are divisible by 16 (i.e., multiples of 16), among the tones havingtone indexes ranging from −496 to 496, and, then, 0 may be mapped to theremaining tones. More specifically, in an 80 MHz channel, among thetones having tone indexes ranging from −496 to 496, a 1×HE-STF tone maybe positioned at a tone index that is divisible by 16 excluding the DC.Accordingly, a total of 62 1×HE-STF tones having the 1×HE-STF sequencemapped thereto may exist in the 80 MHz channel.

5. Embodiment Applicable to the Present Disclosure

The WLAN 802.11 system considers transmission of an increased streamusing a band wider than that of the existing 11ax or more antennas toincrease the peak throughput. In addition, the present specificationalso considers a method of aggregating and using various bands.

The present specification proposes phase rotation that is additionallyapplied to a data part in a duplicated transmission situation toincrease a transmission range in a 6 GHz LPI (Low Power Indoor) system.

A representative structure of an 802.11be PPDU (EHT PPDU) is shown inFIG. 10 . The U-SIG consists of a version independent field and aversion dependent field. In addition, U-SIG consists of two symbols, twosymbols are jointly encoded, and each 20 MHz consists of 52 data tonesand 4 pilot tones. Also, U-SIG is modulated in the same way as HE-SIG-A.That is, U-SIG is modulated by BPSK 1/2 code rate. In addition, EHT-SIGcan be encoded with variable MCS, and may have a 1 2 1 2 . . . structureas in the existing 11ax or another structure (e.g. 1 2 3 4 . . . or 1 21 2 3 4 3 4 . . . structure). In addition, the EHT-SIG may be configuredin units of 80 MHz, and in a bandwidth of 80 MHz or higher, the EHT-SIGmay be duplicated in units of 80 MHz.

Meanwhile, 802.11be can support an indoor environment using low power ina vast area of 6 GHz. In this case, the data part can be repeatedly sentto obtain more reliable performance. In addition, 802.11be supports20/40/80/160/80+80/320/160+160 MHz (additionally 240/160/80 MHz), anddata can be duplicated and transmitted in a specific bandwidth. In thisspecification, this transmission is called duplicated transmission, andother names may be used in practice. When 80 MHz transmission isconsidered, a PPDU configuration for duplicated transmission isproposed, and it can be simply illustrated as shown in FIG. 16 .

FIG. 16 shows an example in which data is duplicated for each 40 MHzwhen transmitting an 80 MHz PPDU.

In this specification, this transmission is called duplicatedtransmission, and other names may be used in practice. Duplicatedtransmission can be used only for i) 80/160/80+80/320/160+160 MHz PPDUtransmission, ii) only for MCS0 or MCS0+DCM, and iii) only for 1 stream.iv) may be limited to SU transmission only, and v) Puncturing may not beapplied.

The same data may be simply repeated in two blocks (each 40 MHz datapart in FIG. 16 ), but the constellation may be different forperformance improvement. For example, let's assume that the number ofsubcarriers into which data is inserted excluding the pilot in the firstblock and the second block is N, and the constellation in eachsubcarrier of the first block is d_1,n (n=0˜N−1). At this time, theconstellation in the second block can be defined as follows.

d_2,n=d_1,n*exp(j*n*π(n=0 to N−1, k=1 or −1 or other integer)

In this specification, when duplicated transmission is considered in80/160/80+80/240/160/80/320/160+160 MHz situations, phase rotationapplied to the data part to reduce PAPR is proposed.

5.1 80 MHz

The configuration of the actual data part can be proposed in variousways. FIG. 17 is a tone plan of 802.11be 80 MHz, and based on this, aconfiguration of a data part will be proposed.

FIG. 17 is a diagram illustrating a tone plan of an 80 MHz band definedin 802.11be.

In the present specification, a new 80 MHz tone plan as shown in FIG. 17or a method of configuring a data part based on a repeated tone plan ofthe 80 MHz tone plan is proposed. In the tone plan of FIG. 17 , a2×242-tone RU of each 40 MHz segment may be considered as a 484-tone RU,and a 996-tone RU may be the same as a 996-tone RU of the existing 11ax.

<Method 1>

There are two 484 RUs, and each 484 RU data can be duplicated. In thiscase, phase rotation of 1 or −1 or j or −j can be additionally appliedto 484 RU with high frequency (or to the 40 MHz part with highfrequency). Multiplying by 1 may be desirable, which is equivalent tosimple iteration and may be beneficial from a PAPR and implementationperspective.

Or, after the data part is simply duplicated, the same phase rotation asthe phase rotation applied to the legacy preamble of 40 MHz bandwidth,U-SIG, and EHT-SIG may be applied to the data part of the 40 MHz partwith a low frequency or a high frequency (only one of the two). Thecorresponding sequence is [1 j], and among the data parts of the 40 MHzpart with low or high frequency, 1 is the value multiplied by the low 20MHz part, and j is the value multiplied by the high 20 MHz part.Alternatively, a sequence of [1 −1] or [−1 1] may be used, and thesequence shows better performance in terms of PAPR. [1 −1] is equivalentto multiplying by −1 only the 20 MHz part with high frequency among the40 MHz data part parts with low or high frequency after the data part issimply duplicated. [−1 1] is equivalent to multiplying by −1 only the 20MHz part with a low frequency among the 40 MHz data part with a low orhigh frequency after the data part is simply duplicated. That is, aphase rotation of −1 may be applied only to one 20 MHz part among all 80MHz data parts, and may be advantageous in terms of implementation andPAPR.

The same phase rotation as the phase rotation applied to the legacypreamble, U-SIG, and EHT-SIG of the 80 MHz bandwidth may be applied tothe entire 80 MHz data part. The corresponding sequence is [1 −1 −1 −1],and each coefficient can be multiplied sequentially from the lowest 20MHz of the data part.

<Method 2>

By dividing the 996 RU in half, data of the low frequency 498 subcarrier(including the pilot subcarrier) and the high frequency 498 subcarrier(including the pilot subcarrier) can be duplicated. In this case, phaserotation of 1 or −1 or j or −j can be additionally applied to the 498subcarrier with high frequency (or to the 40 MHz part with highfrequency). Multiplying by 1 may be desirable, which is equivalent tosimple iteration and may be beneficial from a PAPR and implementationperspective.

Or, after the data part is simply duplicated, phase rotation applied toa legacy preamble of 40 MHz bandwidth, U-SIG, and EHT-SIG may be appliedto the data part of the 40 MHz part with a low frequency or a highfrequency (only one of the two). The corresponding sequence is [1 j],and among the data parts of the 40 MHz part with low or high frequency,1 is the value multiplied by the low 20 MHz part, and j is the valuemultiplied by the high 20 MHz part. Alternatively, a sequence of [1 −1]or [−1 1] can be used and shows better performance in terms of PAPR. [1−1] is equivalent to multiplying by −1 only the 20 MHz part with highfrequency among the 40 MHz data part parts with low or high frequencyafter the data part is simply duplicated. [−1 1] is equivalent tomultiplying by −1 only the 20 MHz part with a low frequency among the 40MHz data part with a low or high frequency after the data part is simplyduplicated. That is, a phase rotation of −1 may be applied only to one20 MHz part among all 80 MHz data parts, and may be advantageous interms of implementation and PAPR.

Or, after the data part is simply duplicated, phase rotation applied tothe legacy preamble of the 80 MHz bandwidth, U-SIG, and EHT-SIG can beapplied to the entire 80 MHz data part. The corresponding sequence is [1−1 −1 −1], and each coefficient can be multiplied sequentially from thelowest 20 MHz of the data part.

5.2. 160/80+80 MHz

There are two 996 RUs, and each 996 RU data can be duplicated. In thiscase, phase rotation of 1 or −1 or j or −j can be additionally appliedto 996 RU with high frequency (or to the 80 MHz part with highfrequency). Multiplying by 1 may be desirable, which is equivalent tosimple iteration and may be beneficial from a PAPR and implementationperspective.

Or, after the data part is simply duplicated, phase rotation applied tothe legacy preamble of the 80 MHz bandwidth, U-SIG, and EHT-SIG can beapplied to the data part of the 80 MHz part with a low or high frequency(only one of the two). The corresponding sequence is [1 −1 −1 −1], andamong the data parts of the 80 MHz part with low or high frequency, itcan be sequentially multiplied from the low 20 MHz part to the high 20MHz part. There are sequences with similar performance, [1 1 1 −1], [1 1−1 1], [1 −1 1 1], [−1 1 1 1], [−1 1 −1 −1], [−1 1 −1 −1], [−1 −1 −1 1],etc, but the performance is similar, so it may be advantageous to usethe previously implemented [1 −1 −1 −1] in terms of implementation.

Alternatively, after the data part is simply duplicated, the data partof the 80 MHz part having a low frequency or the high frequency (onlyone of the two) may be multiplied in sequence from the low 20 MHz partby the following sequence. [1 1 −1 −1], [1 −1 1 −1], [1 −1 −1 1], [−1 11 −1], [−1 1 −1 1], [−1 −1 1 1]. These sequences may be advantageous interms of PAPR. Among these, [1 1 −1 −1] is equivalent to multiplyingonly the 40 MHz part with high frequency among the 80 MHz data partparts with low or high frequency after the data part is simplyduplicated by −1. [−1 −1 1 1] is the same as multiplying only the 40 MHzpart with low frequency among the 80 MHz data part parts with low orhigh frequency after the data part is simply duplicated. Therefore, itmay be advantageous to apply [1 1 −1 −1] or [−1 −1 1 1] in terms ofimplementation as well as PAPR. In other words, a phase rotation of −1may be applied to only one part of the four parts of 40 MHz in theentire 160 MHz data part.

The preamble part can be configured in a way defined in the entirebandwidth used for duplicated transmission, but like the data part, theentire preamble part may be duplicated. In this case, phase rotation of1 or −1 or j or −j may be applied to the 80 MHz part having a highfrequency of the preamble part. For example, the EHT-LTF sequence of 80MHz can be duplicated, and phase rotation of 1 or −1 or j or −j can beadditionally applied to the 80 MHz part with high frequency. Multiplyingby 1 may be desirable, which is equivalent to simple iteration and maybe beneficial from a PAPR and implementation perspective.

Alternatively, phase rotation applied to the legacy preamble of the 80MHz bandwidth, U-SIG, and EHT-SIG may be applied to the preamble part ofthe 80 MHz part with a low or high frequency (only one part of the two).The corresponding sequence is [1 −1 −1 −1], and among the preamble partsof the 80 MHz part with low or high frequency, it can be sequentiallymultiplied from the low 20 MHz part to the high 20 MHz part. There aresequences with similar performance, [1 1 1 −1], [1 1 −1 1], [1 −1 1 1],[−1 1 1 1], [−1 1 −1 −1], [−1 −1 1 −1], [−1 −1 −1 1] etc, but since theperformance is similar, it may be advantageous to use the previouslyimplemented [1 −1 −1 −1] in terms of implementation.

Alternatively, the preamble part of the 80 MHz part having a lowfrequency or the high frequency (only one part of the two) may bemultiplied in sequence from the low 20 MHz part by the followingsequence. [1 1 −1 −1], [1 −1 1 −1], [1 −1 −1 1], [−1 1 1 −1], [−1 1 −11], [−1 −1 1 1]. Among them, [1 1 −1 −1] is equivalent to multiplying by−1 only the 40 MHz part with high frequency among the 80 MHz preambleparts with low or high frequency. [−1 −1 1 1] is equivalent tomultiplying by −1 only the 40 MHz part with a low frequency among the 80MHz Preamble parts with a low or high frequency. Therefore, it may beadvantageous to apply [1 1 −1 −1] or [−1-1 1 1] in terms ofimplementation as well as PAPR. In other words, a phase rotation of −1may be applied to only one of the four 40 MHz parts in the entire 160MHz preamble part.

5.3. 240/160+80 Mhz

There are three 996 RUs, and each 996 RU data can be configuredidentically. In this case, phase rotation of 1 or −1 or j or −j can beadditionally applied to 996 RUs other than the 996 RU with the lowestfrequency (or to the 80 MHz part other than the 80 MHz part with thelowest frequency). It may be desirable from the PAPR point of view toapply the following phase rotation sequence from the lowest frequency tothe highest frequency in units of 80 MHz.

[1 1 −1] or [1 −1 −1]

The preamble part may be configured in a way defined in the entirebandwidth used for duplicated transmission, but the entire preamble partmay be repeated like the data part. In this case, phase rotation of 1 or−1 or j or −j may be applied to other 80 MHz parts except for the 80 MHzpart having the lowest frequency of the preamble part. For example, theEHT-LTF sequence of 80 MHz can be duplicated, and phase rotation of 1 or−1 or j or −j can be additionally applied to the 80 MHz part with highfrequency. The phase rotation sequence may be applied identically to thephase rotation sequence applied to the data part.

5.4. 320/160+160 MHz

<Method 1>

There are four 996 RUs, and each 996 RU data can be configuredidentically. In this case, phase rotation of 1 or −1 or j or −j can beadditionally applied to 996 RUs other than the 996 RU with the lowestfrequency (or to the 80 MHz part other than the 80 MHz part with thelowest frequency). It may be desirable from the PAPR point of view toapply the following phase rotation sequence from the lowest frequency tothe highest frequency in units of 80 MHz.

[1 1 1 −1] or [1 1 −1 1] or [1 −1 1 1] or [1 −1 −1 −1]

The preamble part may be configured in a way defined in the entirebandwidth used for duplicated transmission, but the entire preamble partmay be repeated like the data part. In this case, phase rotation of 1 or−1 or j or −j may be applied to other 80 MHz parts except for the 80 MHzpart having the lowest frequency of the preamble part. For example, theEHT-LTF sequence of 80 MHz can be duplicated, and phase rotation of 1 or−1 or j or −j can be additionally applied to the 80 MHz part with highfrequency. The phase rotation sequence may be applied identically to thephase rotation sequence applied to the data part.

<Method 2>

There are two 2×996 RUs and each 2×996 RU data can be duplicated. Inthis case, phase rotation of 1 or −1 or j or −j can be additionallyapplied to the 2×996 RU with high frequency (or to the 160 MHz part withhigh frequency). Multiplying by 1 may be desirable, which is equivalentto simple iteration and may be beneficial from a PAPR and implementationperspective.

Alternatively, after the data part is simply duplicated, phase rotationapplied to the legacy preamble of the 160 MHz bandwidth, U-SIG, andEHT-SIG can be applied to the data part of the 160 MHz part with a lowor high frequency (only one of the two). The corresponding sequence is[1 −1 −1 −1 1 −1 −1 −1], and among the data parts of the 160 MHz partwith low or high frequency, it can be sequentially multiplied from thelow 20 MHz part to the high 20 MHz part.

Alternatively, after the data part is simply duplicated, the data partof the 160 MHz part having a low frequency or the high frequency (onlyone of the two) may be multiplied in sequence from the low 20 MHz partby the following sequence. [1 1 1 1 −1 −1 −1 −1], [−1 −1 −1 −1 1 1 1 1].These sequences may be advantageous in terms of PAPR. Among these, [1 11 1 −1 −1 −1 −1] is the same as multiplying only the 80 MHz part withhigh frequency among the 160 MHz data part with low or high frequencyafter the data part is simply duplicated. [−1 −1 −1 −1 1 1 1 1] is thesame as multiplying only the 80 MHz part with low frequency among the160 MHz data part with low or high frequency after the data part issimply duplicated. Therefore, it may be advantageous to apply [1 1 1 1−1 −1 −1 −1] or [−1 −1 −1 −1 1 1 1 1] in terms of implementation as wellas PAPR. In other words, a phase rotation of −1 may be applied to onlyone of the four parts of 80 MHz in the entire 320 MHz data part.

The preamble part can be configured in a way defined in the entirebandwidth used for duplicated transmission, but like the data part, theentire preamble part may be duplicated. In this case, phase rotation of1 or −1 or j or −j may be applied to the 160 MHz part having a highfrequency of the preamble part. For example, the EHT-LTF sequence of 160MHz can be duplicated, and phase rotation of 1 or −1 or j or −j can beadditionally applied to the 160 MHz part with high frequency.Multiplying by 1 may be desirable, which is equivalent to simpleiteration and may be beneficial from a PAPR and implementationperspective.

Alternatively, phase rotation applied to the legacy preamble of the 160MHz bandwidth, U-SIG, and EHT-SIG can be applied to the preamble part ofthe 160 MHz part with a low or high frequency (only one part of thetwo). The corresponding sequence is [1 −1 −1 −1 1 −1 −1 −1], and amongthe preamble parts of the 160 MHz part with low or high frequency, itcan be sequentially multiplied from the low 20 MHz part to the high 20MHz part.

Alternatively, the preamble part of the 160 MHz part having a lowfrequency or the high frequency (only one part of the two) may bemultiplied in sequence from the low 20 MHz part by the followingsequence. [1 1 1 1 −1 −1 −1 −1], [−1 −1 −1 −1 1 1 1 1]. These sequencesmay be advantageous in terms of PAPR. Among them, [1 1 1 1 −1 −1 −1 −1]is equivalent to multiplying by −1 only the 80 MHz part with highfrequency among the 160 MHz preamble part with low or high frequency.[−1 −1 −1 −1 1 1 1 1] is equivalent to multiplying by −1 only the 80 MHzpart with low frequency among the 160 MHz preamble part with low or highfrequency. Therefore, it may be advantageous to apply [1 1 1 1 −1 −1 −1−1] or [−1 −1 −1 −1 1 1 1 1] in terms of implementation as well as PAPR.In other words, a phase rotation of −1 may be applied to only one of thefour 80 MHz parts in the entire 320 MHz preamble part.

It may be desirable to use the preamble part defined in thecorresponding bandwidth without duplication.

The phase rotation method applied to the proposed data part in eachbandwidth above may be applied including the pilot tone as well as thedata tone, or may be applied only to the data tone excluding the pilottone. The former is advantageous from a PAPR point of view, but thelatter may be easier depending on the implementation.

FIG. 18 is a flowchart illustrating the operation of the transmittingapparatus/device according to the present embodiment.

The above-described STF sequence (i.e., EHT-STF/EHTS sequence) may betransmitted according to the example of FIG. 18 .

The example of FIG. 18 may be performed by a transmitting device (APand/or non-AP STA).

Some of each step (or detailed sub-step to be described later) of theexample of FIG. 18 may be skipped/omitted.

In step S1810, the transmitting device may obtain control informationfor the STF sequence. For example, the transmitting device may obtaininformation related to a bandwidth (e.g., 80/160/240/320 MHz) applied tothe STF sequence. Additionally/alternatively, the transmitting devicemay obtain information related to a characteristic applied to the STFsequence (e.g., information indicating generation of a 1×, 2×, or 4×sequence).

In step S1820, the transmitting device may configure or generate acontrol signal/field (e.g., EHT-STF signal/field) based on the obtainedcontrol information (e.g., information related to the bandwidth).

The step S1820 may include a more specific sub-step.

For example, step S1820 may further include selecting one STF sequencefrom among a plurality of STF sequences based on the control informationobtained through the step S1810.

Additionally/alternatively, step S1820 may further include performing apower boosting.

Step S1820 may also be referred to as a step of generating a sequence.

In step S1830, the transmitting device may transmit asignal/field/sequence configured in the step S1820 to the receivingapparatus/device based on the step S1830.

The step S1820 may include a more specific sub-step.

For example, the transmitting apparatus/device may perform a phaserotation step. Specifically, the transmitting apparatus/device mayperform the phase rotation step in units of 20 MHz*N (N=integer) for thesequence generated through the step S1820.

Additionally/alternatively, the transmitting apparatus/device mayperform at least one of CSD, Spatial Mapping, IDFT/IFFT operation, GIinsertion, and the like.

A signal/field/sequence constructed according to the presentspecification may be transmitted in the form of FIG. 10 .

FIG. 19 is a flowchart illustrating the operation of the receivingapparatus/device according to the present embodiment.

The above-described STF sequence (i.e., EHT-STF/EHTS sequence) may betransmitted according to the example of FIG. 19 .

The example of FIG. 19 may be performed by a receiving apparatus/device(AP and/or non-AP STA).

Some of each step (or detailed sub-step to be described later) of theexample of FIG. 19 may be skipped/omitted.

In step S1910, the receiving apparatus/device may receive a signal/fieldincluding an STF sequence (i.e., an EHT-STF/EHTS sequence) in stepS1910. The received signal may be in the form of FIG. 10 .

The sub-step of step S1910 may be determined based on the step S1830.That is, in the step S1910, an operation for restoring the results ofthe phase rotation CSD, spatial mapping, IDFT/IFFT operation, and GIinsert operation applied in step S1830 may be performed.

In step S1910, the STF sequence may perform various functions, such asdetecting time/frequency synchronization of a signal or estimating anAGC gain.

In step S1920, the receiving apparatus/device may perform decoding onthe received signal based on the STF sequence.

For example, step S1920 may include decoding the data field of the PPDUincluding the STF sequence. That is, the receiving apparatus/device maydecode a signal included in the data field of the successfully receivedPPDU based on the STF sequence.

In step S1930, the receiving apparatus/device may process the datadecoded in step S1920.

For example, the receiving apparatus/device may perform a processingoperation of transferring the decoded data to a higher layer (e.g., MAClayer) in step S1920. In addition, when generation of a signal isinstructed from the upper layer to the PHY layer in response to datatransferred to the upper layer, a subsequent operation may be performed.

Hereinafter, the above-described embodiment will be described withreference to FIG. 1 to FIG. 19 .

FIG. 20 is a flowchart showing a procedure for transmitting a PPDU, by atransmitting STA, according to the present embodiment.

The example of FIG. 20 may be performed in a network environment inwhich a next generation WLAN system (IEEE 802.11be or EHT WLAN system)is supported. The next generation wireless LAN system is a WLAN systemthat is enhanced from an 802.11ax system and may, therefore, satisfybackward compatibility with the 802.11ax system.

The example of FIG. 20 is performed by a transmitting STA, and thetransmitting STA may correspond to an access point (AP). A receiving STAof FIG. 20 may correspond to an STA that supports an Extremely HighThroughput (EHT) WLAN system.

This embodiment proposes a method and apparatus for duplicating andtransmitting data in order to increase a transmission distance intransmission of an EHT PPDU. The 802.11be wireless LAN system cansupport transmission in an indoor environment using low power in abroadband of 6 GHz. Accordingly, in order to obtain more reliableperformance, a method of repeatedly transmitting data in the frequencydomain in the EHT PPDU is proposed.

In step S2010, a transmitting station (STA) generates a PhysicalProtocol Data Unit (PPDU).

In step S2020, the transmitting STA transmits the PPDU to a receivingSTA through a first band.

The PPDU may be an Extremely High Throughput (EHT) PPDU supporting an802.11be wireless LAN system. The PPDU includes a preamble and a datafield. The preamble is a Legacy-Short Training Field (L-STF), aLegacy-Long Training Field (L-LTF), a Legacy-Signal (L-SIG), anUniversal-Signal (U-SIG), an EHT-SIG, an EHT-STF and an EHT-LTF.

The first band includes first to fourth subblocks. The first to fourthsubblocks may be arranged in order of frequency from low to high. Thedata field includes first data for the first and second subblocks andsecond data for the third and fourth subblocks. The second data isgenerated based on data obtained by duplicating the first data andapplying phase rotation to the third subblock. A value of the phaserotation applied to the third subblock is −1. Phase rotation is notapplied to the remaining subblocks, i.e., the first, second, and fourthsubblocks (or simply multiplied by 1).

That is, the data field is divided into two partial bands in the entireband (the first band), and is configured of duplicated (or repeated)data for each partial band (assuming that the size is the same). Theabove-described transmission method may be referred to as a duplicatedtransmission. In this case, by transmitting the PPDU by applying phaserotation to data for the subblock having the third lowest frequency inthe entire band, there is an effect that reliable performance can beobtained even for transmission over a longer distance.

In order to perform the duplicated transmission, the followingconditions must be satisfied. First, the first data may be generated byperforming constellation mapping on encoded data bits based on BinaryPhase Shift Keying (BPSK) and Dual Carrier Modulation (DCM) in the firstand second subblocks. That is, constellation mapping may be performed onthe encoded data bits based on BPSK and DCM.

If an encoded data bits are modulated based on a first Modulation andCoding Scheme (MCS), the first MCS may be named EHT-MCS 14 as amodulation scheme to which BPSK and DCM are applied. In this case, theEHT-MCS 14 may be referred to as an MCS defined for duplicatedtransmission. In this case, the coding rate may be 1/2. Information onthe first MCS may be included in a user field of the EHT-SIG. The PPDUmay be a single-user (SU) PPDU supporting a single spatial stream(N_(SS)=1).

Conventionally, after encoding a data bit stream (or bit stream), databits can be distributed for each specific subblock. The encoded databits may be distributed for each specific subblock based on a segmentparser or in an implementation method without a segment parser. Forexample, the first data bit may be distributed to the first and secondsubblocks, and the second data bit may be distributed to the third andfourth subblocks. The distributed data bits may be subjected toconstellation mapping, LDPC tone mapping, and pilot insertion for eachspecific subblock.

However, in this embodiment, encoded data bits are distributed only tothe first and second subblocks, constellation mapping (or constellationmapping and LDPC tone mapping) is performed on the encoded data bitsdistributed to the first and second subblocks (based on BPSK and DCM),the constellation mapped data is duplicated as it is in the third andfourth subblocks, and a method of including data to which phase rotationis applied only to the third subblock is proposed. That is, the encodeddata bits are distributed only to the first and second subblocks,constellation mapping (or Low Density Parity Check (LDPC) tone mapping)is performed on the encoded data bits in the first and second subblocksbased on BPSK and DCM, and the second data may be obtained byduplicating the constellation mapped (or LDPC tone mapped) data andapplying phase rotation to the third subblock.

A first pilot tone for the first data may be inserted into the first andsecond subblocks after the first data is generated. A second pilot tonefor the second data may be inserted into the third and fourth subblocksafter the second data is generated. However, the phase rotation may notbe applied to the first and second pilot tones.

This embodiment proposes a method of transmitting data by duplicatingdata when transmitting at 80 MHz, 160 MHz, and 320 MHz, but applyingphase rotation only to the third lowest subblock (partial band) in theentire band (first band). That is, data duplication is performed byviewing the entire band as four subblocks, and the sizes of the foursubblocks are the same.

If the first band is an 80 MHz band, the first subblock may be a first20 MHz band having the lowest frequency, the second subblock may be asecond 20 MHz band having a second lowest frequency, the third subblockmay be a third 20 MHz band having a third lowest frequency, and thefourth subblock may be a fourth 20 MHz band having the highestfrequency.

If the first band is a 160 MHz band, the first subblock may be a first40 MHz band having the lowest frequency, the second subblock may be asecond 40 MHz band having the second lowest frequency, the thirdsubblock may be a third 40 MHz band having the third lowest frequency,and the fourth subblock may be a fourth 40 MHz band having the highestfrequency.

If the first band is a 320 MHz band, the first subblock may be a first80 MHz band having the lowest frequency, the second subblock may be asecond 80 MHz band having the second lowest frequency, the thirdsubblock may be a third 80 MHz band having the third lowest frequency,and the fourth subblock may be a fourth 80 MHz band having the highestfrequency.

FIG. 21 is a flowchart showing a procedure for receiving a PPDU, by areceiving STA, according to the present embodiment.

The example of FIG. 21 may be performed in a network environment inwhich a next generation WLAN system (IEEE 802.11be or EHT WLAN system)is supported. The next generation wireless LAN system is a WLAN systemthat is enhanced from an 802.11ax system and may, therefore, satisfybackward compatibility with the 802.11ax system.

The example of FIG. 21 may be performed by a receiving STA, and thereceiving STA may correspond to an STA supporting an Extremely HighThroughput (EHT) WLAN system. A transmitting STA of FIG. 21 maycorrespond to an access point (AP).

This embodiment proposes a method and apparatus for duplicating andtransmitting data in order to increase a transmission distance intransmission of an EHT PPDU. The 802.11be wireless LAN system cansupport transmission in an indoor environment using low power in abroadband of 6 GHz. Accordingly, in order to obtain more reliableperformance, a method of repeatedly transmitting data in the frequencydomain in the EHT PPDU is proposed.

In step S2110, a receiving station (STA) receives a Physical ProtocolData Unit (PPDU) from a transmitting STA through a first band.

In step S2120, the receiving STA decodes the PPDU.

The PPDU may be an Extremely High Throughput (EHT) PPDU supporting an802.11be wireless LAN system. The PPDU includes a preamble and a datafield. The preamble is a Legacy-Short Training Field (L-STF), aLegacy-Long Training Field (L-LTF), a Legacy-Signal (L-SIG), anUniversal-Signal (U-SIG), an EHT-SIG, an EHT-STF and an EHT-LTF.

The first band includes first to fourth subblocks. The first to fourthsubblocks may be arranged in order of frequency from low to high. Thedata field includes first data for the first and second subblocks andsecond data for the third and fourth subblocks. The second data isgenerated based on data obtained by duplicating the first data andapplying phase rotation to the third subblock. A value of the phaserotation applied to the third subblock is −1. Phase rotation is notapplied to the remaining subblocks, i.e., the first, second, and fourthsubblocks (or simply multiplied by 1).

That is, the data field is divided into two partial bands in the entireband (the first band), and is configured of duplicated (or repeated)data for each partial band (assuming that the size is the same). Theabove-described transmission method may be referred to as a duplicatedtransmission. In this case, by transmitting the PPDU by applying phaserotation to data for the subblock having the third lowest frequency inthe entire band, there is an effect that reliable performance can beobtained even for transmission over a longer distance.

In order to perform the duplicated transmission, the followingconditions must be satisfied. First, the first data may be generated byperforming constellation mapping on encoded data bits based on BinaryPhase Shift Keying (BPSK) and Dual Carrier Modulation (DCM) in the firstand second subblocks. That is, constellation mapping may be performed onthe encoded data bits based on BPSK and DCM.

If an encoded data bits are modulated based on a first Modulation andCoding Scheme (MCS), the first MCS may be named EHT-MCS 14 as amodulation scheme to which BPSK and DCM are applied. In this case, theEHT-MCS 14 may be referred to as an MCS defined for duplicatedtransmission. In this case, the coding rate may be 1/2. Information onthe first MCS may be included in a user field of the EHT-SIG. The PPDUmay be a single-user (SU) PPDU supporting a single spatial stream(N_(SS)=1).

Conventionally, after encoding a data bit stream (or bit stream), databits can be distributed for each specific subblock. The encoded databits may be distributed for each specific subblock based on a segmentparser or in an implementation method without a segment parser. Forexample, the first data bit may be distributed to the first and secondsubblocks, and the second data bit may be distributed to the third andfourth subblocks. The distributed data bits may be subjected toconstellation mapping, LDPC tone mapping, and pilot insertion for eachspecific subblock.

However, in this embodiment, encoded data bits are distributed only tothe first and second subblocks, constellation mapping (or constellationmapping and LDPC tone mapping) is performed on the encoded data bitsdistributed to the first and second subblocks (based on BPSK and DCM),the constellation mapped data is duplicated as it is in the third andfourth subblocks, and a method of including data to which phase rotationis applied only to the third subblock is proposed. That is, the encodeddata bits are distributed only to the first and second subblocks,constellation mapping (or Low Density Parity Check (LDPC) tone mapping)is performed on the encoded data bits in the first and second subblocksbased on BPSK and DCM, and the second data may be obtained byduplicating the constellation mapped (or LDPC tone mapped) data andapplying phase rotation to the third subblock.

A first pilot tone for the first data may be inserted into the first andsecond subblocks after the first data is generated. A second pilot tonefor the second data may be inserted into the third and fourth subblocksafter the second data is generated. However, the phase rotation may notbe applied to the first and second pilot tones.

This embodiment proposes a method of transmitting data by duplicatingdata when transmitting at 80 MHz, 160 MHz, and 320 MHz, but applyingphase rotation only to the third lowest subblock (partial band) in theentire band (first band). That is, data duplication is performed byviewing the entire band as four subblocks, and the sizes of the foursubblocks are the same.

If the first band is an 80 MHz band, the first subblock may be a first20 MHz band having the lowest frequency, the second subblock may be asecond 20 MHz band having a second lowest frequency, the third subblockmay be a third 20 MHz band having a third lowest frequency, and thefourth subblock may be a fourth 20 MHz band having the highestfrequency.

If the first band is a 160 MHz band, the first subblock may be a first40 MHz band having the lowest frequency, the second subblock may be asecond 40 MHz band having the second lowest frequency, the thirdsubblock may be a third 40 MHz band having the third lowest frequency,and the fourth subblock may be a fourth 40 MHz band having the highestfrequency.

If the first band is a 320 MHz band, the first subblock may be a first80 MHz band having the lowest frequency, the second subblock may be asecond 80 MHz band having the second lowest frequency, the thirdsubblock may be a third 80 MHz band having the third lowest frequency,and the fourth subblock may be a fourth 80 MHz band having the highestfrequency.

6. Device Configuration

The technical features of the present disclosure may be applied tovarious devices and methods. For example, the technical features of thepresent disclosure may be performed/supported through the device(s) ofFIG. 1 and/or FIG. 11 . For example, the technical features of thepresent disclosure may be applied to only part of FIG. 1 and/or FIG. 11. For example, the technical features of the present disclosure may beimplemented based on the processing chip(s) 114 and 124 of FIG. 1 , orimplemented based on the processor(s) 111 and 121 and the memory(s) 112and 122, or implemented based on the processor 610 and the memory 620 ofFIG. 11 . For example, the device according to the present disclosurereceives a Physical Protocol Data Unit (PPDU) from a transmittingstation (STA) through a first band, and decodes the PPDU.

The technical features of the present disclosure may be implementedbased on a computer readable medium (CRM). For example, a CRM accordingto the present disclosure is at least one computer readable mediumincluding instructions designed to be executed by at least oneprocessor.

The CRM may store instructions that perform operations includingreceiving a Physical Protocol Data Unit (PPDU) from a transmitting STAthrough a first band and decoding the PPDU. At least one processor mayexecute the instructions stored in the CRM according to the presentdisclosure. At least one processor related to the CRM of the presentdisclosure may be the processor 111, 121 of FIG. 1 , the processing chip114, 124 of FIG. 1 , or the processor 610 of FIG. 11 . Meanwhile, theCRM of the present disclosure may be the memory 112, 122 of FIG. 1 , thememory 620 of FIG. 11 , or a separate external memory/storagemedium/disk.

The foregoing technical features of the present specification areapplicable to various applications or business models. For example, theforegoing technical features may be applied for wireless communicationof a device supporting artificial intelligence (AI).

Artificial intelligence refers to a field of study on artificialintelligence or methodologies for creating artificial intelligence, andmachine learning refers to a field of study on methodologies fordefining and solving various issues in the area of artificialintelligence. Machine learning is also defined as an algorithm forimproving the performance of an operation through steady experiences ofthe operation.

An artificial neural network (ANN) is a model used in machine learningand may refer to an overall problem-solving model that includesartificial neurons (nodes) forming a network by combining synapses. Theartificial neural network may be defined by a pattern of connectionbetween neurons of different layers, a learning process of updating amodel parameter, and an activation function generating an output value.

The artificial neural network may include an input layer, an outputlayer, and optionally one or more hidden layers. Each layer includes oneor more neurons, and the artificial neural network may include synapsesthat connect neurons. In the artificial neural network, each neuron mayoutput a function value of an activation function of input signals inputthrough a synapse, weights, and deviations.

A model parameter refers to a parameter determined through learning andincludes a weight of synapse connection and a deviation of a neuron. Ahyper-parameter refers to a parameter to be set before learning in amachine learning algorithm and includes a learning rate, the number ofiterations, a mini-batch size, and an initialization function.

Learning an artificial neural network may be intended to determine amodel parameter for minimizing a loss function. The loss function may beused as an index for determining an optimal model parameter in a processof learning the artificial neural network.

Machine learning may be classified into supervised learning,unsupervised learning, and reinforcement learning.

Supervised learning refers to a method of training an artificial neuralnetwork with a label given for training data, wherein the label mayindicate a correct answer (or result value) that the artificial neuralnetwork needs to infer when the training data is input to the artificialneural network. Unsupervised learning may refer to a method of trainingan artificial neural network without a label given for training data.Reinforcement learning may refer to a training method for training anagent defined in an environment to choose an action or a sequence ofactions to maximize a cumulative reward in each state.

Machine learning implemented with a deep neural network (DNN) includinga plurality of hidden layers among artificial neural networks isreferred to as deep learning, and deep learning is part of machinelearning. Hereinafter, machine learning is construed as including deeplearning.

The foregoing technical features may be applied to wirelesscommunication of a robot.

Robots may refer to machinery that automatically process or operate agiven task with own ability thereof. In particular, a robot having afunction of recognizing an environment and autonomously making ajudgment to perform an operation may be referred to as an intelligentrobot.

Robots may be classified into industrial, medical, household, militaryrobots and the like according uses or fields. A robot may include anactuator or a driver including a motor to perform various physicaloperations, such as moving a robot joint. In addition, a movable robotmay include a wheel, a brake, a propeller, and the like in a driver torun on the ground or fly in the air through the driver.

The foregoing technical features may be applied to a device supportingextended reality.

Extended reality collectively refers to virtual reality (VR), augmentedreality (AR), and mixed reality (MR). VR technology is a computergraphic technology of providing a real-world object and background onlyin a CG image, AR technology is a computer graphic technology ofproviding a virtual CG image on a real object image, and MR technologyis a computer graphic technology of providing virtual objects mixed andcombined with the real world.

MR technology is similar to AR technology in that a real object and avirtual object are displayed together. However, a virtual object is usedas a supplement to a real object in AR technology, whereas a virtualobject and a real object are used as equal statuses in MR technology.

XR technology may be applied to a head-mount display (HMD), a head-updisplay (HUD), a mobile phone, a tablet PC, a laptop computer, a desktopcomputer, a TV, digital signage, and the like. A device to which XRtechnology is applied may be referred to as an XR device.

The claims recited in the present specification may be combined in avariety of ways. For example, the technical features of the methodclaims of the present specification may be combined to be implemented asa device, and the technical features of the device claims of the presentspecification may be combined to be implemented by a method. Inaddition, the technical characteristics of the method claim of thepresent specification and the technical characteristics of the deviceclaim may be combined to be implemented as a device, and the technicalcharacteristics of the method claim of the present specification and thetechnical characteristics of the device claim may be combined to beimplemented by a method.

What is claimed is:
 1. A method performed in a wireless local areanetwork (WLAN) system, the method comprising: receiving, by a receivingstation (STA), a Physical Protocol Data Unit (PPDU) from a transmittingSTA; and decoding, by the receiving STA, the PPDU, wherein the PPDUincludes a preamble and a data field, wherein a bandwidth of the PPDUincludes a lower resource unit (RU) and a higher RU, wherein the datafield includes first data for the lower RU and second data for thehigher RU, wherein in the data field, the higher RU is a duplicated RUfrom the lower RU along with a partial sign change, and wherein thepartial sign change is applied to a lower half frequency domain of thehigher RU.
 2. The method of claim 1, wherein a value of the partial signchange applied to the lower half frequency domain of the higher RU is−1, wherein the first data is generated by performing constellationmapping on encoded data bits based on binary phase shift keying (BPSK)and dual carrier modulation (DCM) in the lower RU, wherein the encodeddata bits are distributed only to the lower RU, wherein a first pilottone for the first data is inserted into the lower RU after the firstdata is generated, wherein a second pilot tone for the second data isinserted into the higher RU after the second data is generated, whereinthe partial sign change is not applied to the first and second pilottones.
 3. The method of claim 2, wherein based on the bandwidth of thePPDU being 80 MHz, a lower half frequency domain of the lower RU is a242-tone RU having the lowest frequency, a higher half frequency domainof the lower RU is a 242-tone RU having a second lowest frequency, thelower half frequency domain of the higher RU is a 242-tone RU having athird lowest frequency, and a higher half frequency domain of the higherRU is a 242-tone RU having the highest frequency.
 4. The method of claim2, wherein based on the bandwidth of the PPDU being 160 MHz, a lowerhalf frequency domain of the lower RU is a 484-tone RU having the lowestfrequency, a higher half frequency domain of the lower RU is a 484-toneRU having a second lowest frequency, the lower half frequency domain ofthe higher RU is a 484-tone RU having a third lowest frequency, and ahigher half frequency domain of the higher RU is a 484-tone RU havingthe highest frequency.
 5. The method of claim 2, wherein based on thebandwidth of the PPDU being 320 MHz, a lower half frequency domain ofthe lower RU is a 996-tone RU having the lowest frequency, a higher halffrequency domain of the lower RU is a 996-tone RU having a second lowestfrequency, the lower half frequency domain of the higher RU is a996-tone RU having a third lowest frequency, and a higher half frequencydomain of the higher RU is a 996-tone RU having the highest frequency.6. The method of claim 2, wherein the encoded data bits are modulatedbased on a first Modulation and Coding Scheme (MCS), wherein thepreamble includes an Extremely High Throughput-Signal (EHT-SIG), whereininformation on the first MCS is included in a user field of the EHT-SIG,wherein the PPDU is a single-user (SU) PPDU supporting a single spatialstream.
 7. A receiving station (STA) configured to operate in a wirelesslocal area network (WLAN) system, the receiving STA comprising: amemory; a transceiver; and a processor being operatively connected tothe memory and the transceiver, wherein the processor is configured to:receive a Physical Protocol Data Unit (PPDU) from a transmitting station(STA), and decode the PPDU, wherein the PPDU includes a preamble and adata field, wherein a bandwidth of the PPDU includes a lower resourceunit (RU) and a higher RU, wherein the data field includes first datafor the lower RU and second data for the higher RU, wherein in the datafield, the higher RU is a duplicated RU from the lower RU along with apartial sign change, and wherein the partial sign change is applied to alower half frequency domain of the higher RU.
 8. A method performed in awireless local area network (WLAN) system, the method comprising:generating, by a transmitting station (STA), a Physical Protocol DataUnit (PPDU); and transmitting, by the transmitting STA, the PPDU to areceiving STA, wherein the PPDU includes a preamble and a data field,wherein a bandwidth of the PPDU includes a lower resource unit (RU) anda higher RU, wherein the data field includes first data for the lower RUand second data for the higher RU, wherein in the data field, the higherRU is a duplicated RU from the lower RU along with a partial signchange, and wherein the partial sign change is applied to a lower halffrequency domain of the higher RU.
 9. The method of claim 8, wherein avalue of the partial sign change applied to the lower half frequencydomain of the higher RU is −1, wherein the first data is generated byperforming constellation mapping on encoded data bits based on binaryphase shift keying (BPSK) and dual carrier modulation (DCM) in the lowerRU, wherein the encoded data bits are distributed only to the lower RU,wherein a first pilot tone for the first data is inserted into the lowerRU after the first data is generated, wherein a second pilot tone forthe second data is inserted into the higher RU after the second data isgenerated, wherein the partial sign change is not applied to the firstand second pilot tone.
 10. The method of claim 9, wherein based on thebandwidth of the PPDU being 80 MHz, a lower half frequency domain of thelower RU is a 242-tone RU having the lowest frequency, a higher halffrequency domain of the lower RU is a 242-tone RU having a second lowestfrequency, the lower half frequency domain of the higher RU is a242-tone RU having a third lowest frequency, and a higher half frequencydomain of the higher RU is a 242-tone RU having the highest frequency.11. The method of claim 9, wherein based on the bandwidth of the PPDUbeing 160 MHz, a lower half frequency domain of the lower RU is a484-tone RU having the lowest frequency, a higher half frequency domainof the lower RU is a 484-tone RU having a second lowest frequency, thelower half frequency domain of the higher RU is a 484-tone RU having athird lowest frequency, and a higher half frequency domain of the higherRU is a 484-tone RU having the highest frequency.
 12. The method ofclaim 9, wherein based on the bandwidth of the PPDU being 320 MHz, alower half frequency domain of the lower RU is a 996-tone RU having thelowest frequency, a higher half frequency domain of the lower RU is a996-tone RU having a second lowest frequency, the lower half frequencydomain of the higher RU is a 996-tone RU having a third lowestfrequency, and a higher half frequency domain of the higher RU is a996-tone RU having the highest frequency.
 13. The method of claim 10,wherein the encoded data bits are modulated based on a first Modulationand Coding Scheme (MCS), wherein the preamble includes an Extremely HighThroughput-Signal (EHT-SIG), wherein information on the first MCS isincluded in a user field of the EHT-SIG, wherein the PPDU is asingle-user (SU) PPDU supporting a single spatial stream.
 14. Atransmitting station (STA) configured to operate in a wireless localarea network (WLAN) system, the transmitting STA comprising: a memory; atransceiver; and a processor being operatively connected to the memoryand the transceiver, wherein the processor is configured to: generate aPhysical Protocol Data Unit (PPDU); and transmit the PPDU to a receivingSTA, wherein the PPDU includes a preamble and a data field, wherein abandwidth of the PPDU includes a lower resource unit (RU) and a higherRU, wherein the data field includes first data for the lower RU andsecond data for the higher RU, wherein in the data field, the higher RUis a duplicated RU from the lower RU along with a partial sign change,and wherein the partial sign change is applied to a lower half frequencydomain of the higher RU.